Just got back from a long test drive. The new plugs didn't solve the problem. Still getting the occasional stuttering. This time it came when I floored the pedal and revs got above 5000.

Got code 0302: misfire in cylinder 2.

When I pulled the coil packs, I couldn't see any outer wear (though I didn't take them apart). If by "plug boots" you mean the red rubber boot on the end of the coil pack, there was no sign of carbon deposits on them.

So, it seems like the next step is to replace coil packs. I just have to decide whether to replace them all, or try to just replace pack 2.

There goes my Christmas money...

 

Sorry to here that, At least your getting a miss fire code. Most do not. Have you ever replaced the fuel filter? I would look for a vacuum leak too especially by the 2 cylinder.


Replace them all but at last resort....http://www.obd-codes.com/p0300

 

Thanks for the suggestion, SB. I was doing my maintenance at the dealership (up to 65,000mi) and there is no note in my service history indicating that they changed the fuel filter, so I assume they didn't.

A fuel filter change would be cheaper than replacing coil packs, but it sounds like a P.I.T.A. Have to remove center console, then use a special tool (which I don't have) to pull the filter assembly. Service manual says to first check fuel line pressure (using another tool I don't have).

But I guess I should give it a try, since my problem started immediately after filling the tank.

 

P300 is hard to fix. Do you have a KN filter, I missed if you do and what year? Sorry I missed that. If you have a K/N filter with a MAF it could be part of the problem. They can check the coil pack voltage but if its them replace them all unless your getting rid of the car. Keep the good old ones for back up.

 

No K/N filter. Can I check the coil pack voltage at home with a volt meter? What should the voltage be?

 

I know the subject was done else where on this forum. Try using the search box. I am sure you can check it with going to the dealer but I don't know the specs and exactly how to do it because I never had a issue yet. Its not like the good old days where a tune up took a few hours.

 

Last week, my GD3 developed a random misfire, once again. I had this happen a few years back, about 65,000 miles ago. The symptoms you have are similar to what I had. I was able to fix the problem by installing a new set of plugs, (Denso IK22s) gapped at .032".
As I was saying, when my Fit threw a cel again last week, my Scangauge recorded a thrown code of P2138. Yesterday, it threw the same code. Today it happened again.
This afternoon, I readjusted my plugs back to .032" again, and my Fit has been running back to normal. I did several test runs, and it easily revs to 6,500 RPM again without any problems. I am thinking that some of us have coilpacks that are not robust enough to fire the plugs at the optimistic factory .042"-.051" gap setting.
Rather than fork out $600, try regapping your plugs to .032" and see if it helps. I think it's worth a try. BTW, I was able to remove my coilpacks and plugs, regap the plugs, then replace the plugs and coilpacks within 25 minutes. So, time should not be an excuse to possibly save $600!
If your problem still persists, then you probably do have a weak no. 2 coilpack.

 

Misfire happened while stopped at a light today, for the first time. Turned off the defrost, it ran ok. Turned defrost back on, and it was misfiring again.

So I'm guessing this indicates the problem for my car is electrical, and not fuel-filter related. Is that logical?

I may try the spark-plug regapping trick. I worry, though, whether the smaller gap might have damaging side-effects. I'm a total amateur mechanic, but it seems like Honda engines are pretty finely tuned to run in a certain way. What do you guys think?

 

A load test on the battery will tell you if the battery is bad. Shops likes Sears or auto zone has battery testers because they want you to buy a battery from them.

There still can be fuel related problems but the main problem is electrical. A 2008 should have had the fuel filter replaced already especially with ethanol in the gas.

 

Don't read too much into that, as the A/C is programmed to cut in during any of the DEFROST modes. The extra load on the engine may be what is triggering the misfire.


+++++++++

That said, I would replace that #2 coil pack. Time to suck it up and DO IT.

Can't tell from your posts, but have you adjusted the valves yet?

 

Thanks for the advice. This is why FF is such a great forum.

Yeah, I figure I'm going to have to bite the bullet and just replace all four coil packs. I might buy an ohmmeter today and test the old coils, just for s**ts and giggles.

I have not adjusted the valves yet – I'm not hearing any unusual clicking – but that's probably next on the DIY list.

Happy New Year.

 

Thanks again, SB.

I'll probably let the dealer replace the fuel filter. From what it says in the service manual, digging around in the fuel tank might be a little over my head. O'Reilly Auto said they don't even sell the part.

 

FWIW, valves only click when they are LOOSE. Honda valves seem to silently tighten with age. Most of our Fit's valves needed adjustment at 60K, and they were all tight.

Valve adjustment is an investment in TIME, not PARTS. (Long as you have the tools such as the bent-tip feeler gauges)


Remember, the bottom line on this epic 375-post topic is, the stutter can be caused by several factors, either singly or in combination: Coil Packs, Plugs, Valves are the primary culprits.

 

I think lots of the coil problems is from what oil and fuel is used. I never had an issue in my cars but my wife's Civic is running bad. I think carbon build up is the primary cause to most of the issue being discussed. Carbon causes the valves to stick which causes wear, possible oil consumption and raises the temps in the chamber resulting in a snow ball effect of problems. Excessive fuel use, poor running motor etc. I understand its starts at basic maintenance and helped by fuel and oil choices to how your car is going to run in the long run. Its funny my wife uses regular and I use premium which may or may not have ethanol. I assume it dont because of my fuel trims. It all goes to controlling carbon.

 

I don't know if today's fuels cause carbon so much. Ethanol is a great dry-gas and intake cleaner.

IMO you can eliminate a lot of alleged "carbon" problems by running the engine to redline occasionally (helps keep the VTEC "limber" as well). This also increases injector duration which keeps them clean.

Plus, it's FUN.

I do some high-rev driving in my daughter's Fit whenever I get behind the wheel. For that matter, I run "Grandma's Minivan" up to redline once in a while, also.




++++++++++++

I had a Mustang 5.0 years ago...needed to have water sprayed into the intake every year or so to "decarbonize". Same thing with a 70's Triumph Spitfire I restored. Never had to do that with late 90s + engines.

 

I've had bad experiences with ethanol. Since the early 80s. I will buy a fuel injection cleaner and take it out on the tollway. I am leaning on carbon issues because of no CELs and no other problems. Water works really good and used it when things were easier. Use to take a beer bottle and pour it down the carburetor. Got away with that lucky, Did not learn about hydro-lock until a engine in a truck went.

 

Yeah, I used to clean my cars by shooting water down the carbs while running. Smoothed out the cars amazingly. I never had any problems from that practice, though.

I agree that carbon build-up is a major problem with all petrol engines. If you could ensure you ran your engine at a constant RPM you probably would have much less problems. Unfortunately, the constant changes in fuel/air ratios with different operating conditions causes waves of cooling and heating cycles.

 

Spent the morning at the dealer. My wife surprised me and got the car fixed with out me telling her whats wrong. One she went to the manager and complained about the service, then about the TPSM that was on, Bad mpg and the miss when the light was off. Today the miss was gone on the way to the dealer so the cold actually made the car run better. MPG was up last week to 29 which is OK but not what I get in my car. They said they found a nail in the tire and fixed it for free which most likely was there for a month, I did not see or feel the nail when I added air a week ago. They said they could not duplicate the miss but I think they put in a cleaner because the car ran better after we left. She also complained about the battery term and that the hood prop was almost touching and how a week after service we got a letter saying we need 2010 cars.
So as of now the car is fixed and shes looking into a CRV and I am trying to talk her into Fit.

 

John,

First of all let me say thank you very much for starting and following through on this thread. You not only described the very same, vexing problem that I'm experiencing, you did it far better than I ever could and followed up with your solution. I commend you for your thoroughness.

Today I brought my 07 Fit Sport in to the number one Honda dealer in the nation for diagnostics to see if they could tell me what has been causing the hesitations in my car that you so perfectly described. I told them to please make sure they checked it while it was in gear, because the problem does not occur in park. The service rep assured me that the car would be test driven.

Odometer In: 80323

40 Minutes or so later the service rep told me that the diagnostic test was clean and that we might want to consider adjusting the valves (sound familiar?). I asked if it was test driven and he said yes, for 4 miles, without a problem. Just my luck, I thought.

I asked for a computer printout of the diagnostic test but he said there is no printout that accompanies the test.

Odometer Out: 80323 on car. They entered 80327 on printout.

As I was leaving the driveway I looked at my odometer and it was the same mileage as when I brought it in. They hadn't driven it anywhere!!! - even though they entered 4 more miles on the "Odometer Out" spot on the printout summary.

I was shocked beyond belief, and returned to the shop as soon as I could turn around. This added two miles to my odometer reading but still got me back in their driveway two miles under the 4 miles they had entered on the sheet.

After much drama on their part, (I didn't yell or anything, just said the car wasn't driven anywhere), they admitted the car wasn't test driven, and the mechanic foreman took me and the car out for a test drive and indeed he felt several mild versions of the problem first hand (for me it is sometimes extreme and dangerous, especially when merging on the highway). He commented that it was definitely not a valve problem.

Since last week I've been asking them about the coil packs and they've assured me that a coil pack problem would cause the Check Engine Light to come on, so they say it can't be the coil packs. They dismiss my quotations of folks on this forum as irrelevant. The foreman said he'd try switching the coil packs around anyway, and test drive it again.

They came back and said it was the Transmission Torque Converter, but that we could try changing the transmission fluid to see if it makes a difference. No mention was made of the coil pack rotation so I don't know if it was done. I didn't bother asking about the coil packs or the new test drive because at that point I just didn't trust them. They changed the transmission fluid and recommended a new Torque Converter for about $1300.

I finally left 3-some-odd hours after first arriving there, feeling perplexed and used. Needless to say, the car still hesitated at every stop sign and light on the way home. I didn't take the highway because I don't trust it on the highway anymore.

$117 later for the alleged diagnostic test, and I don't even know if they ever hooked it up to the diagnostic machine or if that would catch the faulty coil packs anyway.

I can't get them to even consider the coil packs.

Did your Check Engine Light ever come on?

I am going to write to the owner of this dealership tonight when I calm down a little. He is very well known, a very public figure, and took over his father's business after his father's death. At the very least he should know of the deception his personnel dealt me today.

Thank you again for your diligence on this board. I remain convinced that my problem is really the same thing you experienced.

 

I never got a Check Engine Light - even when I had that same dangerous situation happen when I was merging between two highways and the car seemed to almost completely shut down. I am not sure of the exact name of the device, but they connected a diagnostic device to my car for the test drive and that's when they saw the misfires. They only saw misfires in 2 cylinders and replaced the coil packs on those two cylinders at first, it was better, but I was still getting skips. When I brought it back the next time they just replaced the final two packs and I have been good since then.

I won't say the shop acted instantly because I brought comments from this forum, after being unable to find anything else, they relented. I'm sure as an auto tech, the last thing you want to see is comments from some random people on the internet - I'm sure they see it all the time.

Good Luck!