Hmmm ok so rules out the TB theory.. I think you are on the right track with PCM, that's all it can be now.

 

Quote from another forum:

 

(My brother has a 2007 Wrangler w/3.8L V-6.60K miles. It was trowing a code for mis-fire # 3cyl. New plugs,wires, all is well for about 2-3 weeks, then same thing. Only on cold start. What we found is a small intake gasket leak (coolant) that was making it's way to cyl # 3. After a couple weeks very small amounts of coolant got into the cyl-and it would run rough for 15-30 seconds-then clear up. CEL would then come on Mis-fire Cyl #3. new plug,clear codes-all ok for about 2-3 weeks. maybe the repete coolant on the plug ruined or changed it's resistance-don't know. Replaced intake gasket (you could see where it was leaking at) and problem gone)

Thanks JT, my intake manifold has been off at least twice in this nightmare, I would assume they would change the intake gasket each time. I had read something similiar about coolant in the cylinder but both my mechanic and the dealer did not find any indication of any.

 

Thought so. Just throwing it out there for you.

 

I got the PCM back from being programmed to my vin and installed it yesterday. Of course my check engine light went off when I started it up yesterday (before I installed the other PCM). Hopefully it'll stay off permanently now. I'll post either in a couple weeks or when the light comes back on.

 

I was just starting to get excited about my issue being resolved. I've had a couple times when I would get a rough idle just briefly at startup but no CEL, that changed this morning, I knew it was going to come on as it idled rough for 20-30 seconds. Nobody knows what else to look at. Is there a way to contact Jeep's engineers directly?

 

Still having the same issue, I've found that if I pull my battery cables and leave them off overnight I can get at least a week before it starts again. I've been looking at vehicles to replace it but just can bring myself to pull the trigger, #1 I can't really afford anything I like that's out there, #2 New Jeeps are wicked expensive and my trade is not worth as much as I owe and #3 I love my Jeep. Still looking for ideas though.

 

My misfiring has come back... a while ago I did a standard tune up, cleaned the throttle body, upper plenum, and changed intake manifold gasket, sealed the cracked exhaust manifolds, and changed crank sensor, and ignition coil..ran great for several months... Now its shudders again pretty bad while idling with the AC on and during acceleration at lower RPMS... does fine on the highway and when RPMS are higher. Cylinder 2 and 5 will trip a misfire code if I punch the gas when trying to accelerate.

Wish me luck...I'm going to try and replace the fuel injectors for the hell of it...

 

man, I'm sorry to hear that. At least mine is consistent (somewhat). It only does it at start up and lasts less than a minute, then it runs great until I shut it off and start it back up. doesn't do it every start but it does on most. I had an appt. to go back to the dealer, check engine light went off by itself (second time ever), it just came back on yesterday. I'll see if it goes out again, if not in it goes.

 

I was wondering if the TIPM could be the cause of my misfire, it supplies the power to the PCM correct? If I pull my battery cables the problem goes away for as long as 3 weeks.