Hello,
I have been chasing this issue since December '23. First with parts and sensors only to realize that the ECU was bad. I ordered capacitors, by all videos on YouTube and posts on this forum I needed 3 of the same type capacitors. NOPE!! Not "MY" ECU, this one has one 470uF big guy and two of the smaller 220 or something like that. The 470uF capacitor actually exploded and leaked a bunch of black liquid onto the circuit board causing a short between traces and fried half the board under all that gel. So, no resurrecting my old board unless I pay a board house to actually reconstruct it which would cost me more than to buy a reconditioned ECU. I'm trying to avoid spending $400 - $500 on a reprogrammed similar ECU out of a 92-94 Cherokee that may or may not work... I've read posts on this form where people have bought the reprogrammed units, and they still don't work or they run horrible.
Anyone out there who has made engine upgrades and had to change out the ECU and is sitting on this part number ECU from an original 1991 4.0L Automatic Cherokee Sport w/ AC no cruise control and no anti-lock brakes... let me know. I'll buy it from you, I'll pay for shipping. Assuming you removed it as part of an upgrade and not because it no longer worked. If it's no longer working, I'll take it off your hands for free and pay for shipping and will try to fix it as long as you haven't already tried with no luck.

Any help is MUCH appreciated.