Hello All,

I bought a 2003 350z 6speed that had a small miss. I thought it'd be a simply spark plug or fouled injector and im losing my mind. It would run fine for a few hundred RPM and the drop power and sound like a cammed out carbed V8 thats about to stall. Replaced valve covers due to some oil in the spark tubes thinking it was the spark tube O rings aswell as new plugs (gapped properly). Didn't fix my issue at all. Did a compression test and was within tolerance across all cylinders, no drops over 10psi. Pulled the intake manifold and every intake port is full of fresh and burnt oil sludge. So my guess is bad Intake Valve Stem Seals. I really want y'alls opinion before i start tearing the motor down. At highway speeds my eyes burned from gas fumes and it would die/not want to start sporadically. Some times i could go 15 minutes with it running perfect, and then it would misfire continuously. Any ideas? Thanks you guys.

 

Hey, did you look for any leak on the manifold and hoses?
Br,
Al

 

can you upload a video? The symptoms youre describing it sounds like coil pack #4 and coil pack #6 got switched up. If you can take the plenum off and take a picture of how the coil packs are wired up will help.