So I'm at my wits end with the cavalier. I replaced fuel injectors 1 and 4 which was throwing a P0300 seemed to resolve the misfire. Then I picked up a P0303 or cylinder 3 misfire. After replacing fuel injector number 3 I'm now getting a P0300 code again. After doing some digging a few things that I noticed. It idles better but not smooth. At full speed at 60-65 mph I don't get any misfire nor can tell. Is my IAC possibly clogged or bad, what about the fue filter? All help appreciated
Cavalier still having misfire at idle
- Thread starter 97prizm
- Start date
ignition coils? Try swapping #3 with another. Bad plug?
I have doubts that those fuel injectors which were replaced were bad if so, you would likely have gotten codes P0301 and P0304 and your engine would be running good without any codes. How do the plugs look?Things to check would be fuel pressure and vacuum leaks, especially associated with the PCV and brake booster.. Those would affect all cylinders. I would also look at fuel trims which would tell you a lot on how the fuel mixture is , lean or rich. Wouldn't hurt to clean the AIC just to rule that out. However, that would cause surging, too fast or slow of an idle.
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I would also do a fuel pressure test, the pump, pressure regulator may be getting tired or a dirty filter. Are these old side feed injectors? where did you get them OE are over $300 a piece.
A vacuum leak will typically throw P0171 and P0174 codes.
I initially had a P0301 and P0304 code. I replaced the number 1 and 4 injectors. Then I had a P0303 so I replaced the number 3 injector. Now it's a random misfire that isn't as bad but is noticeable and likely won't pass emissions. The weird thing is that I didn't have any issues initially but a leaky injector and rough idle. I dumped a whole bottle of Cataclean in the tank. Not sure if that flushed out accumulated dirt/varnish.
Good. I just replaced the leaking water pump yesterday.
