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Hi guys, I hope someone can shed some light on what I should do...
3 weeks ago on start up the engine light came on and the error code was P0304 Cylinder 4 Misfire Detected, it was running lumpy. Considering that my last spark plug and plug change was about 100k ago I thought I should just change all the Ignition Coils (Bosch), Spark Plugs (NGK LASER IRIDIUM), Ignition cables (MAGNECOR KV85 8.5MM) and I decided to change all the injectors (Bosch) too. 2 days ago after changing all the ignition parts the car started up great and the engine response was back, it was smooth for about half a day. The following day on a start up again I had the same error again. Does anyone have any idea why this could be happening, after switching off and starting again it starts without problems. But you do feel a slight vibration through the steering wheel on idle which does seem like something not running smooth.
The car when driving is fine and smooth, power delivery is good too but I'm sure something is not right with the electronics as this morning it gave me a Cylinder 4 Misfire again, but after a restart it seem ok.
I would appreciate any input, if someone also had a similar problem I would love to hear from you..
This can also be a spun cam lobe, that’s how it starts. Not saying it is, but it seems to be a problem that is hard to diagnose. # 4 was one of the the cylinders that destructed itself in the 112k I bought. The previous owner spent lots of money trying to figure it out. Ran well off idle, but spun I believe the exhaust lobe I would go for a compression check on that cylinder and rule that out.
there’s the aftermath, and upon checking the cam, the lobes are off. Hopefully yours is an injector or something much simpler
It's a system. If any of the components are borderline, which in an old car is certainly the case, unexpected things happen. I am a throw-parts-at-it guy and these are the parts I would throw at it, to rule them out of the picture.
Today I check the fuel pressure at the rails and its healthy, compression test passed too.
One thing I didn't mention, when cylinder 4 is misfire, I get a whining noise come through my speaker. After a restart and everything is fine again, with the whining gone.?? So strange?
Last edited by johnng117; Jul 11, 2023 at 10:47 AM.
Today I check the fuel pressure at the rails and its healthy, compression test passed too.
One thing I didn't mention, when cylinder 4 is misfire, I get a whining noise come through my speaker. After a restart and everything is fine again, with the whining gone.?? So strange?
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Lost need help - Cylinder 4 Misfire Detected
