P0303 misfire on cylinder 3 but car runs really well!!

rlees85

Ex. Club Member
Every so often my ECU has an error saying its detected a misfire on cyl. 3. I tried resetting it but after a few days to a week the code comes back. The car seems to run really well! Although sometimes it does smog people lol (the exhaust acts as if the car is running much richer then it should, but is not burning any oil).

the first thing I have tried is moving the coilpack and spark plugs around (so cylinder 3's coilpack and plug is now on cyl. 2 and vice versa) to see if the misfire moves with it.

The only thing is I am 99.9% sure its not the ignition system.

Recently I had an exhaust valve replaced on cyl. 3 as it was snapped off by a dodgy plug.

My quesion is after that kind of work does it take a while for it to settle or has the mechanic just basically done a #### job?

Knew I should have just done it myself...

Any thoughts?
 
as suspected, compressions abit lower on cyl3. (11 bar when all the others are 14 bar).

rang the guy who did it, refusing to do anything about it...

looks like im going to have to sort this out myself lol
 
Back
Top