Reset the ecu. Sounds like its going haywire in closed loop.

 

Might also be the common loose dash cluster problem causing the dash display problems. Try hitting the instrument cluster (towards the firewall) and see if that reseats the instrument cluster pins better. You're just trying to reseat it, not going for a TKO, so don't get too carried away pounding on it.

Here's a link to a post detailing how to reset the ECU. In the first post, begin from step 21 and go to step 25.
https://www.cherokeeforum.com/f2/703...rite-up-66456/

 

???So when he's cold in open loop it's OK, and when it warms up and goes into closed it freaks out???

???And he can "crash" and reboot the computer by disconnecting the battery???

 

believe it or not it worked i just have to replace my TPS and it is jeepin it again thanks everyone for their help i appreciate it

 

everything above helped me out a lot... but what im wondering is if i took a 91 H.O engine (which is ran off a distributor) and ran the same engine off a computer controlled distributor, will i need to wait for the pcm to learn up?

 

Hey there mobin. I think 90 was the last year for Renix, then it's obd 1. (which is when they start "learning"). They are all computer controlled. If you can explain your question a little more fully, and start a new thread somebody who actually understands these things can probably help you. Good luck!

And that said...Yes, I think is your answer.