My stepson's '10 Avenger 2.4 with 153k on it has an intermittent p0302 (cylinder #2 misfire) popping up.

This started about 3 months ago. Sometimes in the morning or after sitting for several hours (we're in SoCal so weather's not a factor) it will run ragged for about 5-10 seconds before smoothing out. Other times it will run fine all the time but every few days it will still log the 0302 when it appears to be running fine from startup thru driving around for a few days.

It has fresh plugs in it. So far I've swapped the coil, plug, and injector with other cylinders but the problem stays on number 2. If I shut it off in time when it starts ragged and pull the plugs, #2 is wet. I can stick my borescope camera down the holes and #2 piston is wet; the others all look fine.

Also pulled the intake, cleaned everything up, and replaced the gasket. Compression is fine across the board.

All the wiring appears to be fine - in SoCal corrosion is rarely a factor. I pulled the big harness connectors off of the PCM. The PCM pins are clean and straight. I pinched the 2 little coil wire connectors closed a little bit to ensure a good connection at the coil.

All of the injectors were pulled, cleaned, and rebuilt with new o-rings and screens.

Anybody have any ideas before I plunk down $$ for a PCM?

Have you hooked up a noid light to the injector?
You can't test an injector circuit with a regular test light because it can fry the ECU. You must use an LED type of tester often called noid lights. If the #2 injector stays lit or doesn't light the same as the others it may very well be the ECU.

Thanks, I'll check into that.

Found this: https://www.youtube.com/watch?v=5MmR-wXddVw

I use an inductive timing light to check injector firing.

I used a 9 volt battery, alligator clips, a hose, fuel, and compressed air to check/clean injectors.

Unfortunately, it was all the same stuff I was looking for with a random misfire on a 2.0 Neon. Sorry, O.P. : I did everything you did and after trying everything imaginable wound up taking it to a shop: burnt valve. Although I checked the PCV, I think the PCV was the problem all along. The intake had traces of oil in it. This is the first engine I ever had with a burnt valve, maybe someone can clear up what causes it?

Sure sounds like an injector bleeding fuel

That was one of my thoughts too, but I've swapped injectors between cylinders and the problem stays on #2.

You mentioned that when you pull #2 plug, it is wet. Can you tell if it is fuel wet or oil wet? Which ever one it is would give an indication as to where to concentrate the search. Also, I would do a leak down test, just to be sure that one of the valves wasn't the culprit.

Good point here-- I know where Dave is going with this. It may just need a new valve cover set. They come with the spark plug seals which are notorious for doing just this. $20.00 if thats the case.

Also, are these coil pack engines, or is there a single coil firing all the cylinders?

Since the compression was checked and is good, id rule out head gasket and or burnt valve.

GTX also makes a great point. If the injectors were swapped and it still is peeing in the cylinder, there's a signal coming from somewhere keeping the injector in a partial live state randomly. I wonder if theres a wire rubbed through on the injector harness....

swap the coil AND plug from cyl #2 to any other cyl. see if the problem follows. If it does could be coil or coil boot or plug. HTH Paul

Thanks for the valve cover gasket suggestion. I'll check that out and replace it all while I'm in there.

I've been holding off on opening up the wiring harness, but I guess it's probably gonna happen sooner or later.