I’m having trouble diagnosing a misfire on cylinder 3 on my Isuzu Rodeo. I’m getting spark, new coil pack and new plug. Cylinder compression dry test is 150 psi. Which is within Specs. OBD freeze frame data for the p0303 trouble code show a 10% positive change in the LTFT bank 1 and 5% positive change in the STFT bank 1.
The trouble code is being recorded only when the engine is under load at about 30mph
Fuel pressure is being reported
bank 2 fuel trims are -.08%. I do have a leaky valve cover gasket on the left side of the engine.
I have a 3.5l engine. Direct injection. This has happened before, I fixed the misfire before by pulling the injectors and manually cleaning them, I also replaced the valve cover gasket and plug seals at that time. Intake and exhaust Valves were cleaned thoroughly.
What could be the problem? Should I just replace all of the injectors on that side? and the valve cover gasket, I don’t want to keep throwing money at it. I’m not sure why the valve cover is leaking again. It was replaced only 4 years ago.