1989 Wrangler bogging down, irratic idling. Need some help
I'm hoping all of your extensive experience will get me out of this one...
I have a 1989 Jeep Wrangler with a 2.5 liter engine. It had been running like a Lexus until the last few weeks. Now, when I run it for 45 minutes or so (sometimes more, sometimes less), it loses power, kicks and bucks, and backfires when I get on the throttle, and gets progressively worse. I also notice that my idle (which had been perfectly smooth and steady), now oscillates up and down when at idle (though still smooth). I recently had a valve job done, new coil, wires, plugs, distributor cap, new fuel filter, new temp sensor, rebuilt throttle body, new fuel injector, new MAP sensor, O2 sensor, and new vacuum lines. The mechanic that did the valve job said that my fuel pressure was good. I have no Cat.
I am now looking at the Ignition Control Module, Throttle position sensor, or ECU (hell, there's not much else left!). Anyone have any thoughts before I sink yet more money into this project?? ;-) I should also point out that most of the time it's running GREAT, then after 40 minutes or so it starts running like hell, kicking, bucking, and backfiring. I could really use some help on this one!