tubbed71

Hey guys Im new here and Im posting for a friend of mine. He has a 89 jeep grand cherokee 4.0 liter. I do all the work on this jeep. So far I have replaced the motor and rear end and done lots of little things to it. He has a new problem with it that I cant figure out. He has taken it to the local shop and they can't find the problem either. Around 1500 rpm it starts running rough and wants to shut off. When you get on the gas and get above 1500 rpm it does fine. It only does this sometimes, it could go days without doing this. The shop near our house put a new crank position sensor in and it ran ok for about a month then started acting up again. Could this be a fuel or firing problem? Any help on this would be great.

cherokee77

Hey welcome, they did not make a gc in 89. You have a renix system and it could be a fuel or electrical problem. Check the pressure at fuel rail, and report back. I will post a link of all the electical equipment on the renix system.

cherokee77

http://www.lunghd.com/Tech_Articles/...iagnostics.htm

Take a look there also.

Also take a look at greatlakesxj really good website to get you started.

tubbed71

Ok i drove this jeep earlier today and here is what it did, When driving kinda slow and around 1500 rpm it feels like its missing. Then as soon as you give it a little gas it clears right up. When you come to a stop it acts like its going to die, and then again as soon as you hit the gas it has plenty of power and clears up. It only does this some times not all the time. Then when I got back to the house I shut it off and then started it back up and it went up to 3000 rpms just sitting in the driveway.