Decided to try and tidy this post up to make things easier for others.
So, I have been having this issue where my 2015 Fit (Ex-L fwiw) has been seemingly, idling rough. It was a little "jumpy" feeling at stop lights, which progressively has been getting worse. It seemed to happen when the car had warmed up (less noticeable or at all when the car had just been started). Putting it in park when stopped, seemed to make the bucking less noticeable. I have not noticed anything odd when moving (no noticeable loss of power, hesitation, or rough running while driving). If I had to sit at a light for more than a few seconds, it began feeling like my car would stall if I didn't put my car into park,and push the gas pedal down. I couldn't see the RPM needle going down too low (normally idling around 600-800 rpms), but it would dip a tad, then bounce back up. So, I assumed the issue I had was a "low" or "rough" idle.

I have talked to loads of folks and done lots of searches online. And I have gotten dozens of suggestions, some conflicting with others. This is what I had tried, and the results:

1st -Using Fuel Injector Cleaner: I had actually gone through a few bottles of this stuff. It didn't seem to make much (if any) of an impact.

2nd - Replacing the air filter: Probably something you should do, especially if it is really dirty. A new one can be purchased for as little as $15, and it takes all of two minutes, and zero tools to replace. This is something I think you should never pay a mechanic for, because even an idiot (like me) can do it themselves. This did NOT fix my issue.

3rd -Replacing the spark plugs: done, but probably didn't need it at 68k anyway. Did not help.

4th -Cleaning the throttle body: this is the most suggested solution to a rough idle like mine. I was very intimidated by taking it off, initially. But with a socket set, some throttle body cleaner, and a video, I think anyone can try this. All you gotta do is take off the airbox/intake hose. There are a few wires and hoses to unhook. The picture below shows the part I couldn't figure out how to remove. Turns out, the airbox has two bolts on either side of the engine air filter box. Once those are removed, and all the connecting wires/hoses are unhooked, the intake hose and airbox pop right off. Then all I had to do was unscrew the 4 bolts to get the TB out. I sprayed it and scrubbed it out with a rag. Unfortunately, while it seemed to have fixed the problem once starting the car back up (and no rough idle), as soon as I started driving home, and stopped at a light, the bucking came back. (I want to note that when I was trying to rev the engine after putting everything back together, I could not hold the RPMs at or above 3000 RPMs. After a minute or two, it would abruptly drop back down to sub 1000RPMs, even when I hadn't let off the accelerator!)

I finally decided to take it to a shop after the TB cleaning didn't solve my issue. They charged me $170 for a diagnostic. There was no check engine light, and the computer wasn't throwing any codes (although, the work order says that the computer was showing misfires on all of the cylinders, apparently). I guess they proceeded with a visual inspection, where they supposedly used a camera and light inside the engine and found: carbon buildup in the fuel induction system, and they could see ample enough light coming through the valve lashes, that they felt the valves needed to be adjusted. They claimed these issues were bad enough that I "shouldn't drive" the car in this condition. But they also said, while these things "needed to be done", and would "likely fix" my issue, they could not guarantee that it would. My friend told me to go get my car from the shop. As an ex shop owner and mechanic, he said you should never let a shop do work on your car, when they don't feel confident it will fix the problem I brought it there for. And he also didn't seem convinced that my car needed any of this stuff done, when I had only 67k mi on it....at least that it shouldn't be as bad as they claimed. By the time I got a hold of the shop, they had already done the induction flush, but hadn't started on the valve adjustment. So the next thing we tried was...

5th - Induction System Flush: This seemed to make my car appear to have been "fixed". It definitely didn't appear to be idling rough (or noticeably so). But, after a couple of days, the rough idle came back. I am actually kind of pissed I let them do this procedure, because I hadn't realized what it entailed. Apparently, a throttle body cleaning is a big part of the labor that they charge you for. They knew I had already done this. So I was wondering WTF they did do for $240 (+$170 for the diagnostic..so $411 I had to put on my CC, which is nearly maxxed out!). Beyond cleaning the TB, all that this procedure has left to do, is an intake flush, which is a bottle of solvent you can buy at NAPA for like, $30-40, as well as some fuel injector cleaner. The latter is even cheaper, AND I had already tried fuel additives, to no avail. Just talking about it now, kind of pisses me off.

In any case, there has been a lot of back and forth as to whether I should have allowed them to also adjust my valves. Of all of the folks here (as well as friends) who even know what that entails, about half of them seem to think it would have been the right thing to do, to allow them to complete the procedure. The logic being, the valve lashing (spacing) between the rocker arms and the top of valve stem. If the gaps grow too large, or get too tight, it will screw with the engine timing causing it to fire incorrectly, which can introduce a rough idle. It seems that this also usually causes poor fuel efficiency as well as loss of engine power. So I can understand why people would suggest it. However, I am starting to lean more towards the camp that feels that this a) isn't likely causing my car's symptoms specifically, and b) that at as low of mileage as my car has, it is pretty unlikely that these valve adjustments would be super necessary at this juncture. After speaking to a Honda certified mechanic over the phone, he said that it is usually not recommended to make any adjustments to the valves, unless there is an obvious issue there. And, that doing so can possibly make things worse. That being said, I decided to tackle the project myself anyway...if nothing else, I wanted to see if the mechanic who had my car was jerking me around when he was telling me how bad they were. It seemed like it wasn't TOO difficult a task, with a few inexpensive tools such as some feelers from , a little (recommended for tightening up the space where there are a couple of sharp corners), and something to pinch off the coolant hoses..as well as this handy video I found on ... So, the next thing I did was to...

5th - ... Adjust the Valve Lashes: it took me a couple of tries to get it right. The first time it got dark, so I had to frantically put my car back together without checking all of the lashes as well as I would like. I took another crack at it today, since it was Saturday, and nice outside. This time, I was a lot more meticulous with my measurements. I double/triple checked all of the lashes with feelers that I had added some tape to the handles of, since they were really slippery last time (all the engine oil floating around in the crankcase). I definitely feel like my engine sounded nice and smooth when idling in park. But I am going to have to drive it around a bit to see if, after warming up, it goes back to acting like it will stall at stop lights/signs. I feel nearly positive that it will.

 

Update. It is in fact idling low. I could see the needle hopping around the 400-600rpm range. Still no service light/indicator..I tried spraying some TB cleaner into the closed air entry area and used a cloth on a coat hanger to wipe excess off as best I could. I hoped a little bit in there may loosen it up a bit. Didn't seem to help. And it's getting worse!

 

I guess I will just keep replying to myself.

I did manage to remove the throttle body today, to give it a good clean, then followed instructions I found for resetting the throttle (turning on for 2 sec, then starting the engine & holding down the accelerator to keep the engine at ~3000 rpm, then letting it idle with no load for 5min after the radiator fan comes on). So now I have (over the course of the last week):

- Used two bottles (at different times) of fuel injector cleaner.
- Replaced the spark plugs, and
- removed and cleaned the throttle body.

And it is still "bucking" when stopped at a stop light. It did seem to idle a lot smoother (but still a little rough) when in park. So I got excited, thinking I had fixed it with the TB cleaning. But as soon as I stopped at a light, it slowly began bucking again. The weird thing is, there is still no check engine/maintenance light coming on. I can barely see the RPM needle bouncing around, as you would seemingly expect with the engine running so rough.

I seriously doubt its something like the engine mounts going bad. It only has ~60k mi on it. I just have no clue what else to even try. I will probably break down and bring it in to the dealership. I am super worried they are going to charge me an arm and a leg. I really hoped to try a few more things on my own. I still can't even (at a minimum) find anything about whether my car has an idle air control valve, and where it is. I am assuming it may be attached to the throttle body. But I don't want to just start taking things apart, just to see what I can find. Ugh...

 

So I have a few ideas to look into.
1) Rough idle can be caused by a leaking vacuum hose. Look for cracked and/or disconnected vacuum hoses.
2) Bad spark plugs. Consider replacing your spark plugs. It's tough on these 2nd gen Fits.
3) Bad coil pack. Also hard to get to.

Bad engine mounts would not account for low idle in my mind.

 

does it still idle rough in neutral?
i found my fit idles naturally around 700 rpm in idle in park after the engine warms up.

 

1. I checked (mostly) the hoses as I took the air intake stuff apart (had to pull the airbox to get to the throttle body, and didn't see anything bad looking). I also had to disconnect and reconnect the hoses when getting to the TB. I am pretty sure the fittings were all reseated properly. The car only has less than 60k on it, so I kind of wouldn't expect cracked hoses..? I also haven't heard anything like an leak in any of the hoses with it running. But maybe its hard to tell if the holes/cracks are really small. But I would also imagine something that small wouldn't cause the car to idle as rough as it has. Again, its really only noticeable (mostly) when in drive, stopped at a light or something. I would guess it would idle rough constantly, even in park or while driving, if it was a bad hose? Who knows. It very well could be. I definitely don't know cars as well as a lot of people here, or I wouldn't be asking

2. addressed (I see you crossed that out, so you must've caught that I had replaced mine) . But I thought mine was a 3rd gen Fit?

3. I think the coils are the most likely culprit. I took them out when changing the spark plugs. It would have taken me no extra time to change them out, if I had new ones at that time. I also found out that there is an extended warranty/parts recall on them, for the 2015. My ex/neighbor/friend has the same make/model/year. She said her car was doing the same (or similar) thing. She brought it into the dealer, who changed hers out at no cost, which apparently fixed the issue!

I unfortunately brought my car into a small shop near me for a diagnostic. They still have it at this moment, for over 4 hrs (as of 12:23pm 5/12/2022). I actually called them to let them know they may want to check the coils, since I found out they are a common issue with this particular model/year. They said they had already checked the recalls for my car, and noticed the coils on the list. But the also said that the Honda site said (in bold letters, apparently) that the "check engine light will come on". However, my friend who had hers replaced, said her light never came on either!

So, now I don't know whether I should call them back and let them know, so they aren't potentially wasting both of our time (only to come back to the coils anyway). I hate to be the guy who comes off as trying to tell someone how to do their job. But I am feeling more and more confident the coils are the issue and wishing I had taken it to the dealership. The problem is, its a haul to get out there, and they couldn't get my car in until next Tuesday (5 days from now). Obviously, if the coils are bad, and its going to save me a bunch of money, there is no doubt I will be taking it to the dealership. I just don't know what to do in the meantime. I have a 30min each way commute to work, and can't afford to not have my car for an extended period.

The funny thing is, the coils were the next thing I was going to try. They are kind of expensive if you buy all four of "the good ones" (not sure if that deserves to be in quotes, if anything other than the OEM ones are actually garbage...)

I guess we will see what the mechanic comes back with!

Thanks for your reply, either way!

 

If neutral also includes being in park, then not really...? Oddly, I remember putting it in park last week, and it would still idle as rough as if I had my foot on the brake in drive, at a light. But after doing some maintenance. I feel like it doesn't idle nearly as rough (or its hardly noticeable) when in park. I actually thought I fixed the problem yesterday after cleaning the throttle body and letting it idle in park for a few minutes. Then when I left work, it started bucking again at the stop light. It is a long one. So I would put it in park, and the rough idle seemed to lessen again. Maybe its just a coincidence or its there just less noticeable in park. So I started wondering again if it might have something to do with the transmission. Partly, my mind went to the tranny because I have noticed some funny things about how it works in my car, from shortly after I bought it. This is a little off topic but, sometimes shortly after starting the car, when I put it into drive, it revs for a second before the gears engage. I need to see about maybe getting it looked at while I still have this stupid 100mi/7yr "powertrain" warranty (which mostly feels like a $4000 waste of money, if I never use it for anything). I have mentioned it at the dealership when getting an oil change and light servicing. They flushed the transmission a couple of times since I bought the car. The laggy start when going into drive, cold, rarely happens. But, it is still there I think., Probably worth having it looked into if I can get some work done for free, while I still have the warranty.

As for the idling/RPMs; Its hard to tell exactly where the needle falls during normal idle in my car. Lately, it does seem to be in about the 700 RPM range (which I have read is pretty normal...which is why my title reads "...low idle?.." ). I wasn't sure if "low idle" was even part of the equation. But I have noticed, when its idling rough (or that's what it feels like), that the needle does seem to be a bit jumpy rather than steady. It just feels and sounds like the engine is about to stall. So I guess that's why I figured the idle was "low". But I think you are right in assuming the general idle range isn't necessarily low, per se. I guess I don't know how else to describe it!

In any event, as I mentioned in reply to another post, my car is currently in the shop for diagnostics. After dropping it off, I finally got a reply from a friend who also has a 2015 Fit (about where she suggested I take it). In her response, she said I should take it to the dealership since she was having nearly identical issues, which resulted in some parts being replaced for free due to a recall. She said that they replaced her fuel injectors. But when I looked into it and called the dealership, its actually the ignition coils that have had a recall. So either she was confused about which part(s) it was (or misremembered) that were bad. OR her car is somehow different than mine. Both are 2015 EX-L Fits..so, doubtful, unless her car is also a different year than she thinks.

I am highly suspicious of the ignition coils at this juncture. The symptoms make sense, there is a known issue with them in this model/year, and I have found other posts on this forum where people fixed their issues by replacing one or more of their cores. So, yeah. I think the cores are the problem. I actually called the mechanic that has my car right now to let them know the cores have been recalled in this year. They kind of wrote it off, saying the Honda recall site says that the "engine light will definitely come on if the cores are the issue". But my friend who took hers in for that exact thing, did not have her light come one, ever. I believe her on that for sure.

 

I see. The transmission on many Fits (we own two of different years, made in japan) seem to engage the torque converter while holding the brake at stop lights most of the time instead of disengaging the clutch. I do wonder if it does that to warm up the cvt fluid though, since it provides lower viscosity at higher temperatures and the press release of the 3rd gen fit mentioned a cvt fluid warmer, which must mean it is an important function since Honda highlighted this component for consumers.

I just disengage the clutch by switching into neutral or park at stoplights when the shaking bothers me.

 

Oh lord! I hope I don't have to resort to that. I would think shaking like this would be bad for the engine mounts over time, or at least annoying AF. The mechanic doing my diagnostic today (or the desk jockey) said that there was a "lot" of buildup on the valves and they were maladjusted. So they are gonna charge me another $811 do a clean and adjustment. He did say that this was "most likely" the cause of the rough idle. But, no guarantee...which is stressful.

I really need to double check and make sure they didn't completely write off the fuel injectors and/or ignition coils and actually checked them. I didn't talk to the mechanic himself, so no idea if he did or not. It sounded like they wrote it off because the Honda recall site said the check engine light would "definitely be on" if these parts of the ignition system were bad. It sounds like there is a good chance they didn't bother to look them over carefully enough. I am going to be pisssssed if my car is still shuttering tomorrow when I go get it. PISSED.

 

So, another quick(ish) update.. After taking advice from a mechanic buddy, I decided to pull my car out of the shop I had brought it to, and will likely be taking it to the dealer in about a week (unless things get way worse between now and my scheduled maintenance appointment.

I talked to a Japanese repair shop that seems to be really reputable. They kind of confirmed that a valve lash adjustment was something the dealership actually advises against..? I never know with so much, varied information, what to believe any more. So just a quick summary:

My car was idling poorly when stopped at lights/signs, like it wanted to stall, and it would kind of "buck". After some quick research, I decided to try: swapping out the spark plugs, removing the throttle body to give it a good clean, and running some fuel injector cleaner through it. Nothing seemed to work. So I decided to take it to a local, regular old mechanic place. They did a diagnostic (which ran me $170). I actually suggested the check the ingition coils and fuel injectors, since I had since found out they often go bad in this year Fit (2015). A good friend had the exact same issue I was having, had no engine light come on, but the dealership wound up replacing the fuel injectors for free. Coincidentally, I saw a recent post talking about this extended warranty and how owners are now receiving notifications about having this fixed at no cost, due to them being bad. So I felt very strongly this was something the mechanic should spend some time looking at. He seemed dismissive due to no check engine light. He said that what he found, was a "really dirty fuel induction, and some valves that were pretty far out of spec (he said they could "see light:" coming through)". I had agreed to let them do the work. that is, until I was advised that this a) shouldn't be the case with my 65kmi car, b) they were charging me way too much ($811), and c) that this likely wasn't even going to fix the issue. the mechanic even said he thought it was the cause, it may not be, but I "should get it done anyway"

When I picked it up this morning, they had already cleaned the fuel induction system already, but hadn't started on the valve adjustment. They charged me $170 for the diagnostic, and another $340 for the induction cleaning. I realized though, that part of the induction cleaning, is doing the throttle body. But I had already DONE that. So I wasn't sure how much else they had done, and why it would still be so expensive. I am not sure. But they said they "flushed out" some "corrosion" that built up around the valve area, or something. It does appear to be running better, at the moment. But they insisted that I should get the valves done at some point anyway, because they were in fact, out of whack, and it could cause bigger problems if left the way they were.

So, I wonder if this is accurate. My buddy, and another mechanic I talked to kind of said the same thing: this model Fit doesn't have the kind of valve lashes that should be messed with, and/or shouldn't have gone out of whack at 65k mi... I want to know if anyone has any thoughts on that bit. Also, does anyone think that a) it needs to be done, possibly, or b) if that would even be the cause of a rough idle when stopped; both when the engine is warm or cold it would seem, but less so when in park, and does not have a noticeable impact on how the car runs when moving. It seems the engine would run terribly when driving as well if the valves were in fact, in desperate need of adjustment. Is this true? Does anyone know?

In any case, I decided to schedule an appointment at the dealership (as I mentioned) once they have a loaner car available, since there is some concern that they will have it for at least a few days (they are also going to look at the transmission, which sometimes slips when the car is cold and put into drive, for a moment...its still in my extended power train warranty, so I figure I should have it looked at and replaced while I can still do so without having to pay an arm and a leg!). they will also do a diagnostic on the ignition system, and said they would waive the fees and replacement cost if they find a problem with the fuel injectors. Same goes for the tranny.

I just wonder if the valve lash adjustment was or could be, the issue, if I shouldn't have let the other mechanics do the work, so that my car would be fixed and I wouldn't have to potentially spend even more money on another diagnostic, only to find out that they wound up having to do the valve lash adjustment anyway. Any thoughts on this? I would also like to report back once I do find the problem in the hopes of helping others who may have the same issue, which does appear to be pretty common.

 

They advise against valve adjustment? Garbage.

Here's why the valves need to be adjusted. The constant pounding action of the valves opening and closing (at high rpm especially) over time, will pound the exhaust valves closed and the intake valves open.

What winds up happening is that the engine can't breathe, especially with the more closed exhaust valves - you'll never completely exhaust fumes through a restricted valve. Fuel efficiency will take a hit, and power will dwindle.

Having the intake valves at the right spec helps too, but in my mind, opening the constricted exhaust is the more critical.

I had an '08 Fit which I had the valves adjusted at about 120K. Immediate increase in power and mileage. Felt like I gained a gear (it was a manual transmission).

When I had my '16 LX fuel injectors replaced at 88K a couple weeks ago, the dealership asked if I wanted to combine labor and save $ by having the plugs replaced and valves adjusted simultaneously. Labor saved because they've already torn down to the injectors. I would have had this done at 90K regardless, so of course I took them up on the offer. Immediately noticed better mileage, though the power gain wasn't quite as noticeable as my '08 Fit - probably because at 88K vs 120K, less time for the valves to go out of whack.

 

OP, did the last shop indicate what exactly "induction cleaning" entailed?

 

I hear you. I totally believe the lash adjustment would make my car run better in general (better power and fuel efficiency or what have you). But do you feel pretty confident that an ill-adjusted valve would only cause rough idle when stopped, or would you expect the engine to be running rougher at all times? So many of the other things I had read, seem to list the coils or throttle body being the most likely culprit. A lot of places mentioned trying the spark plugs or looking for a vacuum hose leak as well. I am sure the hoses aren't leaking, and I cleaned the throttle body myself. I haven't really come across many people suggesting the valve lash adjustment being a likely cause for my scenario specifically. And since the injectors and coils are known to be commonly bad, I highly suspected those things were the culprit. The mechanic didn't seem certain that those things weren't the issue. He just felt that the valve adjustment and induction cleaning were things I should have done either way. The mechanic buddy of mine was only saying that he didn't think the valve adjustment made as much sense as other things, especially with only 65k mi. He was saying, since I am on a super tight budget, there are other things that made more sense that these guys should have looked at more seriously. He also said that he'd read somewhere that the valve system in the newer fits were less likely to go out of whack. When I called another, reputable shop to talk to them, they kind of echoed his sentiment, saying that Honda actually advises against doing valve adjustments on these newer Fits. I am just so confused because I am hearing all kinds of contradictory advice. Now I don't know if I should be kicking myself for not letting them do the valve adjustment. Maybe my car would be back in my possession, fully fixed, as we speak. Now I have an appointment at the dealership in about a week. They are going to check and see if there are any bad parts that are covered by an extended warranty. If they suggest the valve adjustment is the issue after all, well I guess I am out $165 for the second diagnostic. But at least I will have a better idea of what is wrong, and I know they have all the right parts and tools to do the job correctly, right then and there. Although, I don't necessarily trust them 100% to not screw up or try and talk me into tacking on extra stuff anyway...

 

good question. at first, when I watched a video of someone doing an induction cleaning, I was kind of pissed that they talked me into having it done. It looked like the most labor intensive part was taking the throttle body off to clean it. however, I had done that already just a couple of days prior and had told them. Once I realized what the procedure involved, I felt like an idiot because I didn't know, when they suggested it, what an "induction cleaning" means. In any case, I did aske them what they had done, to make sure they didn't charge me $360 to clean something I had already told them I had done. He said they knew already that I had, so obviously didn't bother to clean it themselves. He said what they did do (if I can remember his words correctly (doubtful)) is that they took some stuff apart and flushed something where there was "pretty bad" carbon build up, behind the valves or something? Does that even make sense? A mechanic friend who has been trying to help me navigate all of this stuff ever since I dropped it off, told me that all they likely did was flush the engine with some kind of solvent that you can buy from NAPA for like, $20 or something. I hope that's not all they did! It cost me $455 for the induction cleaning plus diagnostic. I started wondering if these guys weren't ripping me off. I haven't ever owned a newer car. Most of my previous ones have been used clunkers (my last car was a 86 Volvo 240 wagon, that I brought to some dude's house for repairs. Even changing the head gasket (plus several other pretty major things) would only cost me around $300..which is insane. If the thing wasn't too old to use for Lyft/Uber, I would probably still be driving that thing. Now I am trying to navigate the world of modern car woes, where an oil change at Jiffy Lube apparently costs $114 for my fancy synthetic oil. I just don't have any sense of what is normal or reasonable. I am still trying to fix as many things as I can, myself, to save money. But all of the computerized stuff is so intimidating and I feel like I could be running in circles, wasting time and money, when a mechanic can just plug something into my car and know in two minutes. That being said...

Looking at the work order, it looks like they didn't really find any codes besides seeing something about intermittent misfires in cylinders "1,2,3, & 4" and that it seems they only suspected carbon build up. When I spoke to them on the phone, he told me they put a camera type thing in there, and "definitely saw lots of carbon build up" on something they either cleaned or were going to clean. I decided to take my car back without having the valve adjustment they recommended, because I became convinced that (while I am sure it would be a good thing to do) there was a good chance that my crappy idle (while stopped at lights only) was more to do with something in the ignition system..? I don't know. I am super confused right now. Part of me wishes I had let them finish the valve adjustment so I might have a car that runs well again. Instead, I have a car thar runs much better after the induction flush, but I can tell there is still some whacky stuff going on, although very mildly noticeable at this point.

Did I get ripped off?

 

I don't know why this keeps slipping my mind.: when I was revving the engine as part of the throttle reset procedure, I was supposed to hold it at 3000rpm for a few minutes (or until the engine/radiator fan comes on). It seemed that before the fan would come on, the RPMs would abruptly drop down to around 1000 or lower, while I was still holding the pedal down the same amount. Like it was automatically cutting back down on its own, even though I had not released the pedal at all. I could lay off, then push it back down to bring the RPMs back to 3000, but again, it would drop back down to 1000 (or less) again on its own. I feel pretty certain this is another symptom of something going wrong. Part of me also thought it was something the engine would do as a safety measure and normal. But I am kind of doubting and wishing I had mentioned it sooner!

 

If you're worrying whether not having the valve adjustment done was the wrong thing, don't. 67K is pretty early for valve adjustment. I doubt it has anything to do with your issue.

Intermittent misfire codes? Any of these should have activated the check engine light. Has the check engine light ever come on?

For the fuel injector extended warranty, this is the document you need. Honda specifically states MIL (malfunction indicator light, which means check engine light) + any of the listed codes = coverage:

https://static.nhtsa.gov/odi/tsbs/20...08198-0001.pdf

 

I got a recall letter from Honda several days ago...a little late but I had to have my fuel injectors changed about 6 months ago. There is a recall on 2015-2016 fits. The injectors were installed incorrectly and honda is paying for new fuel injectors. It sounds like your is doing what mine was. I had an extended warranty that paid for my repairs but check with the nearest Honda dealer. They should be aware of it and will fix it free of charge.

 

Its funny how much back and forth there is about the valve adjustment. Some are saying it shouldn't need it. I talked to a mechanic at a reputable Japanese import shop near me, who said "Honda actually recommends against having it done (unless absolutely and noticeably necessary), which was echoed by my mechanic buddy (who ran an Audi/VW shop for "many years". Others seem to think that it is a normal and necessary bit of routine maintenance that may not "fix" my problem, but should be done regularly anyway. Then there is the group that feels that it 100%, absolutely could be the cause of my particular issue, and I was wrong to not let the shop do the work (I am sure the mechanics I took my car to fall into that category). I am kind of leaning somewhere in the middle. I think its not a bad thing to do (the valve adjustment), would very likely help my car run better (and maybe extend its life, unless I royally F it up, doing it myself). And who knows? There is a chance that it very well may fix my issue...or at least lessen the effects of whatever else may be wrong with it.

I would have started with the fuel injectors had I known there was a parts recall (or "warranty extension") on my model Fit. I wish to god I had gotten that letter in the mail from Honda, or heard back from my ex down the hall (who has the same year Fit, and turns out to have had the same exact symptoms, which wound up being the injectors...which the dealership replaced for $0), before trying all of these other things (then taking out a credit increase on my CC, to then take it to a local shop, to have them charge me $411 for work that, while nice, didn't fix the issue). That being said, I don't want to completely discredit the valve adjustment theory. I do think ill-adjusted valves can cause a rough idle. There is no denying that. BUT I think it may be a little bit of a stretch to jump directly to the conclusion that the valve adjustment, and that alone, is the likely cause of my issue (specifically). This is especially true when you read the bit about "particularly while warming up" (mine idled rougher even, after warming up). So yeah, there's one more type of "rough idle". I think a lot of people stop reading at "rough idle" and go right to the first thing they think of or heard about, without taking all of the specifics into consideration, I wish there was a flow chart for rough idle, that could navigate you to the most likely culprits by asking questions about when and how your car idles roughly! Maybe that wouldn't work because different causes may potentially manifest themselves in different ways.

I will definitely report back after the valve lash adjustment and then the repairs at the dealership to explain how they affected my problem or if it fixed it. I anticipate the lash adjustment will make my car run much better (at the very least, reducing shutter), and that the idling/misfiring will be completely removed after the fuel injectors are replaced. But who knows! Maybe the valve adjustment will completely fix my car, and the dealership will tell me the fuel injectors are just fine...and then take my money anyway!



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Yeah...I really wish I would have gotten this letter before bringing my car into a shop. I have an appointment in a week and a half (first day they had a loaner available, so I'm not without or have to pay for a rental). they will be checking for the bad fuel injectors, while doing a diagnostic on the ignition system. Apparently they will not charge me if the injectors are bad...but will charge me if they aren't, which is a little annoying. Thats part of the reason why I want to fix as many other possible issues myself (assuming they are relatively cheap and simple) before hand. If I can fix the issue completely with the valve las adjustment, I may hold off on the diagnostic. Apparently, not all Fits are affected. But the warranty extension I thing goes out a year or so. So, if I start having issues again, it would probably then make sense to bring it in.

I am also hoping to have the transmission looked at. as well. I bought one of those stupid, extended power train warranties. I have heard they are usually BS, cover things that aren't likely to go bad, and they may try to finagle their way out of honoring them in various ways. I have had some slipping in the tranny, usually when the car is running cool, and first putting the car into drive (especially, for some reason, if I am coming out of reverse...any thoughts on that from anyone?. They are going to be charging me for two different diagnostics. Both/either will be waived if they find something under warranty, that needs to be fixed. I don't know if I should be grateful the work and diagnostic will be done free in those cases, or if I should be annoyed that I will have to potentially pay twice for diagnosis, just to find out if they sold me some busted crap. I am already bummed that the car came (at 16k mi, somehow) with tires that didn't pass the Lyft inspection, even though it was " Honda certified used", with low mileage. When I called to complain about the tires, they told me that the tread was measured and found to be "passing", even if not "perfect". Therefore, I was going to have to pay for a new set of tires for a car I just bought, just to be able to do the gig work that I sold my Volvo and bought this car to do...was not a good start to my relationship with them. I have since been extremely wary of bringing my car to them, unless its for an oil change (they are much cheaper than Jiffy Lube or any other drive up places in town). Even then, they will try to talk me into having work done that is probably (possibly?) unnecessary . Speaking of which, I do believe they told me I "needed" (or should seriously consider) a valve adjustment, probably about 20k mi ago (I'm currently at ~65k). Hmm...

 

Any time you get a dashboard light, that means an error code has been generated. Need to read the code(s) to understand the problem(s). Many auto parts stores will read the codes for free.