2000 S80 2.9 non-turbo, 150k miles.

I was recently experiencing some fairly erratic idling. The tach would bounce around between 600 and 1000 rpm at idle. Sometime felt like it was about to stall. So I took apart the ETM and cleaned it up real well. Also sprayed clean the MAF. I tried to reset the ETM by disconnecting the negative battery wire while working. I also pulled the ETM fuse (#7), turned the ignition to position II, then turned it off, and re-insertd the fuse.

The erratic idling has been fixed. After warm-up, it now sits at a steady 650 rpm.

However, I can still hear the motor sputter a little bit every few seconds. The tach needle does not move, but the motor stumbles just a bit every few seconds. I've checked the vacuum lines and they all seem to be connected. Any suggestions?

Is it possible that the electronics just need some time to adjust to the clean ETM and MAF? I've driven it for about 5-10 minutes and have stopped/started the car several times now, but it's still happening.

 

So I tested my PCV operation by giving it the rubber glove test. Seems to be working OK.

I do have a check engine light, so I pulled the code....P0302 cylinder 2 misfire.

I guess I need to check the spark plug and the coil to #2 next. The car runs great though (with the exception of a little stumble at idle). Hard to imagine that one of the cylinders isn't firing.