I've been living with a 2.5 that's been a little cranky below 2300 rpm. Always assumed (like many others) that it's just a characteristic of the old AMC designed motor. The right conditions cause it to buck at 2000rpm while pulling a hill and suddenly giving it a little more throttle. Now before you 4.0 owners write this off as a 4-banger problem, bear in mind we have the same harnesses, clockspring, and ECM design. 2 extra cylinders might mask the problem. And please note, no codes or check-engine light is set.
It was only when an ABS light started coming on that I ended up changing the clockspring. While doing some web-surfing on this problem, it was evident many others had the 2000rpm jerk. There were other suggested fixes such as injector wiring mixed up or sensors - for some, it fixed the problem but many others it did not. Some dumped loads of $$$ changing every sensor on the engine. Then I found a post from @Jerry Bransford that explained it the best. A failing clockspring with an intermittent break in one of the wires can back-feed noise down to common grounding point in the ECM. This noise causes an error in the TPS signal to the ECM resulting in the wrong pulse duration to the injectors (= lean!).
What a difference this has made in the idle - 2200 range. This engine now runs as good as the day it came off the lot.
It was only when an ABS light started coming on that I ended up changing the clockspring. While doing some web-surfing on this problem, it was evident many others had the 2000rpm jerk. There were other suggested fixes such as injector wiring mixed up or sensors - for some, it fixed the problem but many others it did not. Some dumped loads of $$$ changing every sensor on the engine. Then I found a post from @Jerry Bransford that explained it the best. A failing clockspring with an intermittent break in one of the wires can back-feed noise down to common grounding point in the ECM. This noise causes an error in the TPS signal to the ECM resulting in the wrong pulse duration to the injectors (= lean!).
What a difference this has made in the idle - 2200 range. This engine now runs as good as the day it came off the lot.