Repeated cylinder 2 misfire
I own a 2001 Honda Civic 4 cylinder EX and my cylinder #2 code keeps
repeatedly coming on. I have replaced the ignition coil and the spark plug
on there and it seems to run fine. After a month the same code will come
on (P0302) and it misfires badly. At that point I replace the spark plug again
and the code comes back on within a month.
This has happened about three times and I am not sure what it is. I have
noticed when the engine is cold, the RPMs will quickly rise above 1000 and
steadily go back down to 1000.
If it helps, I have recently put a cold air intake on there and this wasn't
happening before then.
Other causes would be a bad spark plug wire, and a dirty or dead fuel injector. Since this comes back after a period of time, I would venture to say a dirty injector. May have to replace, but first try a good fuel injection cleaner threw a tank of gas. Wouldn't hurt to replace the spark plug wires.
For the RPM issue check the cold air intake or leaks. Air leaking into the engine past the sensor is un-metered air which will cause idle issues. Regarding the #2 cylinder issue, does the spark plug look fairly clean when you replace it or is it oiled or sooted up?
there is no oil on the spark plug when I take it out. It just looks burned around the bottom.
also the injector going bad makes sense as the misfire gets worse on a new tank. I'll try that out as I have tried a fuel injector cleaner and the wire is a pigtail with an electrical plug on the end and not actual wires (simular to the plug on a sensor).
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