JK was running rough and popped these 2 codes with a CEL.
P0302= Cylinder 2 misfire
P0202= Fuel Injector Circuit open

My current thought is that the P0202 will likely cause a cyclinder misfire (P0302), so should start with the fuel injector circuits for diagnosis.
Going to check wire harness connections since started happening right after snow melted, so thinking water related.

Any other ideas?

 

How's your ignition module connections looking? I replaced mine last night (233k on the original) and five were shiny, one was tarnished. Maybe you got some water down inside there??

 

In my experience misfires have been the spark plugs as a starting point. But if you're like me with really bad luck, you may have a bad head. I found that the lobes ate themselves (https://i.imgur.com/1xnOmzC.jpeg) and had to get a replacement right head this past October @ 125k. At 96k miles I had the left head replaced for the same thing. The other difference was in October it cost me $3000 and that was with Jeep covering half.

Good luck :(

 

I will inspect those, was assuming they were alright based on P0202 code.

What I did so far was disconnect the 2 connectors by the driver side firewall and inspect those like this guy did.

Mine didn't have any corrosion like his but I sprayed them with some electrical cleaner. Cleared the codes then started it back up and it ran fine in the driveway, so thought I found it, maybe a loose connection. Then today took it out for a short drive and started running rough again under load and CEL came back on with the same codes.

 

Yikes! I may pop the valve covers off and inspect those lobes. That would suck. Money situation right now is tight.

 

Just read this thread. Sounds similar to my problem.
https://www.jk-forum.com/forums/stoc...isfire-346110/

So add cats, and PCM as potentials?

I still think the P0202 should give some kind of insight to the problem. The P0302 is a general cylinder misfire, which can be many things but the open circuit P0202 seems like it may point to something electrical causing the misfire.

 

I definitely would if you are mechanically inclined. Here is my original post: https://www.jeepforum.com/forum/f96/...05/index2.html

And here is what I was dealing with: https://imgur.com/a/jqgPjtP

Good luck!

 

That's the 3.6l, hopefully the same issue isn't present in the 3.8, though I can't say for sure.

 

You're right, I didn't even see the part where it was a '09. Lucky you not having a pentastar ;D

 

I've done a lot of research, reading old forum posts of misfires and watching Youtube vids.

Anything coil related seems to only log a single misfire code.

Found this discussion which seems more similar to my problem since it has the misfire code as well as injector circuit open code.
https://www.jk-forum.com/forums/stoc...t-help-334260/

Diagnosis was bad fuel injector. This comment seems like a good reason mine went away and then came back when I started driving it.
"It turns out the new injector at cylinder 1 was bad. When the engine was cold the injector was giving 15 ohms. After driving for 20 minutes I checked the injector again and it was open (0 ohms)."

Does anyone know where I can find a connector pinout diagram for the injector harness? Getting to the injectors, I need to remove the upper manifold, instead thinking I could measure the resistance of injector for cylinder 2 on the other side of the harness to see if the resitance is low or not.

Currently suspecting bad fuel injector on cylinder #2 or bad wiring harness connection on that injector. Ohm meter on opposite side of harness should be able to confirm before taking the upper manifold off. Currently cold out and I hate working in the cold.