I bought a car and a couple months later the engine light came on so I bought one of those OBD scanners and it said it was a misfire on cylinder 4 (P304). I replaced the coil packs, spark plugs, fuel injectors and intake manifold gasket. The engine light went off after and the car ran fine. but now it's doing the same code over and over every week. This car is frustrating me big time. Also when the car is in park and I rev the engine up it won't go past 3500 rpms, thats when it starts like pulsating or revving like its plugged. I'm wasting to much money and fixing things that still don't solve the issue. Can you please help me? Thank you.
Have a mechanic do compression test on cylinder 4. Low compression value could result in misfire as well.
Not the issue