Some things have been happening with my 2012 fit sport and I'm hoping someone went through similar things or have more knowledge that could give me some suggestions.
This just started the minute after my brake pads, rotors, drums, shoes were replaced and after a brake fluid flush.
The car started to jerk a little at high speeds, not much during acceleration but when I would press on gas pedal lightly to maintain speed. It stuttered a couple of times when accelerating after stopping at red light. I thought the car would die. I replaced the spark plugs (haven't replaced coils, spark plugs cables). They were still the factory ones I believe, since I've owned this car since 2014 and never replaced them before. Honda dealership told me to not worry about them unless I'm having issues and I never had issues before until now. I got E3 diamond fire, they said at the store it was one of the best ones and more on the expensive side. My car has 143k miles on it. First question, is it possible something got ruined during brake repairs? I don't see how that would be connected but thought I would ask. Then nothing changes after replacing spark plugs. Someone suggested fuel injector dirty/clogged. Bought fuel system cleaner and after 300 mi my car started to drive much much better. No more jerking at high speeds. I did notice a stutter when reaching around 30-40 mph when changing gears. But almost unnoticeable. Transmission fluid is OK but I should probably change it since it's been awhile. Now what it has started doing is when I rev the engine it doesn't go over 5000. The car stutters and I press all the way down to floor and nothing changes. But when I'm driving in "manual" mode for example using the paddle shifters, I tried going over 5000 before changing gears and no real problem. Just when in P or N. Any idea what I could do to improve acceleration, smooth gear changes and avoid ruining my engine? No CEL has come on yet, no rough idle. Gas mileage decreased some. Should I check the coils? Or is this more an issue with fuel system? Mass air intake system?
Thanks in advanced. I just want to save money and try to do as much as I can by myself. Any suggestions, advice will be appreciated.

 

There are three RPM limits.

6800/Redline is the limit for normal driving.

4500-ish/5000 is the limit when parked or in neutral. This is normal.

3000 is the limit when the car goes into limp mode to protect itself, or at least minimize further damage due to "something." Usually, this is a misfire in the engine.

 

You didn't mention a lot about maintenance you've performed on your car. Regular routine valve adjustments are necessary on Honda engines for them to run properly. If you've never had the valves adjusted, I'd start there. At the same time I personally would go back and install the original brand spark plugs that came in your car- not plugs that are off brand or plugs someone suggests are the latest and greatest. You know the original brand plugs work and are dependable. While you're at it, read some of the posts on this forum about Fit spark plugs getting loose/backing out and determine the proper torque needed on the plugs when you install them.

As for the transmission, transmission fluid changes are fairly inexpensive to do. so do yours again. While you're at it there is an external trans fluid filter that is accessible after you remove the car battery. It sits right above the transmission under the battery box. If that has never been replaced, or it's been a while since replacement, replace it again. I also suggest you use Honda brand trans fluid only, and not any other replacement trans fluid. You'll also need a replacement drain washer for no leaks.

Most of the things I have suggested here are routine things you should be doing to your car as maintenance, and not just me suggesting throwing parts at your car in hopes it fixes your problems. If you have a moderate ability to work on your car, you should be able to do all the labor yourself and the parts should be pretty reasonable. If you've never adjusted valves before, farm that part out to someone experienced- you don't want to get the valves mis-adjusted. Good luck with your repairs!

 

If you haven't replaced the fuel filter, do.