It sounds like your distributor may be 'out' by one tooth ...... (+ -)
I should also add that if you replaced any of the censors (i.e. MAP, CPS, etc.) with an aftermarket brand other than the OE Mopar sensor, there's a very good chance that they're now faulty (if they weren't already before).
Our TJs are notorious for rejecting electronic components from any brand other than Mopar (OE). Many people go to their local auto part store and buy a replacement sensor and report that it doesn't fix their problem. They swap it out for an OE Mopar sensor, and sure enough, that fixes the sensor issue.
Just a thought.
Do you think it's worth another $600 to start replacing the duralast sensors with Mopar OE sensors?
I replaced every sensor I could find with a Duralast Gold lifetime warranty sensor from Auto Zone.
Just for the heck of it, do you mind posting a pic of the front section of your exhaust? Your problem really sounds like plugged up cat or exhaust and since you said you have no cat, we have been ignoring plugged exhaust as a possible cause...
New ECU came in and didn’t not change the problem for better or worse. I carried my Jeep to a mechanic. The original distributor was cracked and I replaced it with a new one. The mechanic said the new one was also cracked and so he replaced it. He set the timing and found a wire in the wiring harness that was frayed and ground out. New distributor and fixed wire got it running good as new. $90 later I’ve put 100 miles on my ol Jeep and it hasn’t missed a beat.
Oopps forgot to leave pictureThank you for this thread. I just bought a new to me 98 TJ Sport, after a no issue test drive, then purchase drive it 2 mi to title place where it exhibited exactly same issue (idle dropping to 200 rpm, wouldn't go over 1500 rpm in neutral). Mines different however as after I drove it further it's improved to an occasional drop in rpm at stop light, to when I got home 30 mi later it was running like new, no issues. Hmm . Since I don't want it leaving me on side of the trail, I'm starting with the basics. I'll clean the IAC, etc. I suspect a vacuum leak as it got better the further I drove it. (As it warmed up something sealed better?) It is a 4.0 L 5 speed manual with 142000 mi. Mostly stock but owner did advise in addition to replacing exhaust manifold (common prob), said replaced head gasket (why ?). Thanks for a great forum.
Widawg