I have read a lot of conflicting info on the interwebs. I have a 1998 Grand Cherokee Laredo, 4.0L, automatic. It has an annoying problem of stalling while driving. It is fine for a few days and then it dies. We let it sit for a few days and try again...same story for multiple weeks in a row. We have replaced plugs, wires, coil, distributor, MAP, CPS and several things I've already forgotten about. We are down to the ECU now. Do I HAVE to use a 1998 ECU, or are there compatible years that I can pull from? I understand that it needs to be same engine and transmission. This is my first forum post so please forgive me if I have broken any etiquette rules.

 

My 97 ZJ does the same thing and it is always the TPS . I think my ECU is bad and burns up the TPS . I am hitting the Bone yard tomorrow for another ECU and see if this will fix it with a new TPS also .

 

It's not an ECU, its the PCM. Next, replacing random parts without troubleshooting *fire the parts cannon* is a fast way to go broke get frustrated and still have a jeep that won't run.
Try taking some fuel pressure measurements. To partly answer your question, a 98 will not interchange with a 97 and below

 

Regardless of the technical nomenclature, you knew to what I was referring, right? Lol.
Maybe random parts wasn't the correct term; I was replacing parts that were indicated through the codes on the OBD scanner.
After replacing the PCM, i realized that one of the wire loom plugs had a broken retaining clip causing it to "wiggle". I zip tied the heck out of it and havent had any issues since. Not the ideal fix, but it has been effective thus far.

 

I know what you meant. Too bad you had to replace plugs, wires, coil, distributor, MAP, CPS and several things plus the pcm only to find a loose connection.

 

I got 4 different PCM's from the Bone yard . All 4 did not work right. thank GOD that LKQ has a money back Warrnenty .I found a place on ebay to send my PCM to fix it for $100.00