My wife's 02 S40 with NA 1.9T has started throwing a P0302 - misfire cylinder 2 - code.

OK 135k miles, I'll change the plugs. No effect.

Change coils. No effect.

Swap the other 2 wires since they are really hard to find. No effect.

Hose down front of engine from cylinder 1 to cylinder 3 looking for vacuum leak. Nothing.

Check fuel pressure in rail. Normal.

Check compression in cylinder #2. Normal.

Swap around fuel injectors. No effect.

Phone a friend. One look and he says "get rid of those autolites." I say "Dude, they're brand new double platinum's". He says "Well, they call them autolites, but they don't. Get rid of them." In goes a new set of NGK Iridium's. This actually helped a bit, but it's still throwing code. Always P0302 - cylinder #2.

Does anyone have ANY ideas what I could be missing here?

Thanks, Doug

 

Go with stock Volvo plugs and that is it. I had the same issue with my 850 and it was the iridium plugs. As for the autolites, those are crap too. These volvos only like there own plugs.

 

Thanks for the suggestion. I might have to give that a try since changing from the autolites to the NGK's made it happen a lot less.

Anybody else have any ideas?

If it helps any it seems to be a cold start issue. If I drive it for only a 1/4 mile and then erase the code it may go 2 or 3 days before setting code again depending on ambient temp.