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Need help with mis at idle

Good luck with that specially since they are very application specific. Did you read the entire thread? Out of 3 harness's all had wire degradation.

Yes I did and thank you very much for your insight! I am going to do what you did and make the repairs but I have to keep it running so my son can get around. I will keep you posted!
 
An intake manifold leak is typically a high, or very high, idle. Idle variation is typically a sensor issue, usually the IAC, the TPS, or O2 sensors that are faulty, have wiring/fuse issues, or are not NTK.
 
At this point, I'd hang a vacuum gauge on it and see what the needle movements tell you. There are many symptoms that can be diagnosed with how the vacuum gauge needle is acting. Likewise, try swapping in a spare TPS to see if there's an improvement. Based on what you've described, there seems to be an air leak at idle which smooths out on acceleration.

Best regards,

CJR

Ok so I decided to challenge myself and replace the injector, o2, coolant temp, TPS, MAP, Intake air, and IAC portions of of the engine wiring harness with a used harness that was intact without any broken insulation. My xj harness had numerous insulation breaks near injector 5/6 and several sensors and injectors had insulation wear at the connectors. I used a harness from an 02 WJ which was the only one available in my area. I had to splice on my XJ o2 connectors, and the TPS connector. It took me about 8-12 hours being extra cautious, to make sure I did not mis anything and to make sure I got it right. A few wires were different colors than my xj so I took extra care to make sure I got it write. I sent most of the wires directly back the the PCM connector but spliced the grounds and 5 volt volt sensor power mid way.

So was there improvement? I would say slightly.

After the harness was done, I replaced the TPS with a new MOPAR and there is no difference so far.

After replacing harness and TPS, I did notice a hiss from the throttle body area at idle and upon investigation found it coming from the the small opening on the inside of the TB that serves the IAC. I assume that is normal???

I Will take a video of the vacuum gauge and post.

Should I consider replacing the PCM?
 
It's very possible. Re-read my post #24 where I replaced the ECU.
 
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