wwilly1968

thanks for letting me in now the issue I'm having hope somebody can help. ok so i have 93 with the 318 awd and i have a major problem, i have replaced the fuel pump,filter,cps,coil,pulled the injectors,have done a fuel pressure test,stays steady at 39-40 pounds at idle,and 45 roughly at 2grand rpm, ok the problem she will start up fine most of the time but when she warms up temp gauge gets to 125 she does not want to idle,nor go down the road smoothly,if i keep constant pressure on the gas she runs but rough,but as soon as i let off the gas she falls flat on her face,then takes quite a few cranks to get her started again and then runs rough as all get out, nobody in my realm of friends who all drive and build jeeps has a clue because they all drive the standard Cherokee 4.0 so nobody i know knows anything about these monsters, i have sunk roughly 300.00 in her in the last two days and still the same outcome usually a smooth start up and then bam on her face, I need help BAD PLEASE AND FAST today I/we pulled the iac again and cleaned it some more acts a lil different but not sure any ideas or words of wisdom will be greatly appreciated...

Bustedback

You could have a bad TPS. Do you have access to a scanner that will let you read the live data stream? Or a DVOM?

karl4x4

My neighbor had similar issues and some other weird ones like having to wait a couple minutes for it to start. He went to the oil fields to work and asked me to fix it for him.. Well, I tested every sensor, bypassed all unnecessary stuff and at the end, I concluded it could only be the PCM. After suspecting that, I researched it and come to find out, it is the MOST common failure for the 90's GC. I pulled it out and could actually smell the burned electronic. bought a re-furbished one on line, put it in and it started better than it did in a long time and ran great....

wwilly1968

ok so the pcm is the one on the fire wall or the one that sits beside the breather box ????

pwb

replace tps and iac.
Mine was much like that after i did a reset of the PCM, the TPS was bad, but if it goes bad over time the PCM learn to live with it, if you then reset the PCM then it see the bad TPS and the fun begins. I replaced the TPS (twice, since the first from rockauto was bad) and IAC, and then it was ok.
You can measure the TPS with a ohm meter, the best one is a analog one, and then measure it and turn it slowly and the ohm meter should respons smooth, if its some drop in there then its bad.