2007 Hyundai Accent
For the last couple of months my car has been misfiring, rough idle, weak acceleration, etc.
To date (since around august) I replaced my spark plugs (car ran great after that for a bit) then in the last month or so it started to misfire somewhat frequently (when I say that I mean the CEL turned on and flashing). Plugged in my code reader and got a misfire in cylinder 4. So for that cylinder we; replaced the boot, the ignition coil, and now the fuel injector (mechanic said it wasn’t consistent with dispensing fuel, so it was replaced, along with every other injector being cleaned and sea foam added to the gas tank).
Just got the car back yesterday and driving to work it has familiar symptoms of before. When accelerating from a stop it kind of stutters and does one hard shake, that happens from around 30-35mph. And then trying to go over 40 it starts to shake and stutter unless I accelerate it more over to around 55-60. I can tell when it’s going to happen because I’ll hear the car reving, then it’ll stop and start to shake hard and have bad power. Weirdly enough, when I turn overdrive off, the problem stops and the car accelerates well.
I drive about 25 minutes to work (I go on a highway to another town) and this only seems to happen after I’ve gone highway speeds for awhile and and into the town where my job is and go in-town speeds.
So guys, anything else you think can stop this bad power and shaking issue? My oil still has about 1.5k miles left, spark plugs are new, cylinder 4 has had pretty much everything replaced in it. No misfires yet, no codes yet.
Mass airflow sensor? MAP sensor? Transmission issues? Should I replace all my coils instead of the one? I’m lost.