I finally gave up trying to fix my Jeep myself and had it towed to a shop. The problem is that it barely idles or just stalls, at idle it sounds like it is running on one cylinder, I have to keep the RPM's above 1500 to keep it running and your can tell one or more cylinders are missfiring (but no codes), both banks fuel trim and O2 sensors indicate that it is running very rich, both banks spark plugs are carboned up, the exhaust smells bad, etc. Compression check pretty good. Good visual spark.
I put in new plugs and replaced the IAC valve and TPS with new MOPAR parts. Didn't help. While the Jeep was down, I fixed the broken exhaust manifold bolts on bank 1 with new MOPAR gasket and bolts.
See the following thread for all the ugly details:
Absolutely no codes on my scanner and the shop can't see anything on their computer, which is much more sophisticated than my scanner. Since the shop can't see anything on their computer, they think that the timing chain may have slipped a tooth or two and threw everything off on the ECM. Or, maybe the ECM programming got messed up but they can't reprogram it with their computer.
Does the timing chain problem sound reasonable? Is there any way to specifically diagnose a timing chain problem without disassembling everything in the front of the engine? The shop is still checking to see if they find anything more definitive.
I took the Jeep to a smaller independent shop because I didn't want to take it to the dealer because of expense. The Jeep has 157,000 miles. Maybe I should have taken it to the dealer? The guy at the shop is very honest and does not want to get involved in heavy engine work on a OHC 4.7. Does anybody have any good recommendations for a shop in the Phoenix area that specializes in Jeeps? One that does heavy work if it is really a major engine problem. Also one that can check and reprogram (flash) the main computer on the Jeep, whatever it's called.
If it is some serious and expensive problem with this engine, I'm thinking about replacing the engine with a rebuilt or remanufactured engine or even a used engine. I'm not bad at doing mechanical things, the reason I took the Jeep to the shop is that I couldn't diagnose the problem. Is replacing the engine something I could take on with the proper equipment to lift out the engine?
I think the Jeep is worth saving if it needs a new or used engine. See photo.
This problem as turned into a @#&**NIGHTMARE