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Renix Cherokee Idling Issue

ssand746

NAXJA Forum User
Location
WI
Hello all,
I am having an issue with my 1989 Jeep Cherokee Limited 4.0L. It has a high idle at start up, going up to 2500 to 3000 rpm and it does't want to come down. Background info is that I have read through the forums and have seen several posts with similar issues and I believe I have tried all the fixes already. I refreshed all the grounds, and added the extra 2 ground cables that is mentioned in the instructions.I have thoroughly cleaned the throttle body. I have checked for vacuum leaks using starting fluid throughout the engine compartment, especially near the intake with no findings. I replaced the MAP sensor and IAC valve. I replaced the TPS even though it checked good based on voltage readings and the ground tested almost no resistance. I have probably done more, this is just what I can think of as of right now. The thing is, with the old or new TPS, once the engine is started and idling high, if you unplug the 3 wire plug from the TPS (engine side), it will idle down to 7-800 rpm. Then if you plug it back in it stays idling fine until the next startup. My question is what could be causing this at this point? Should I just leave it unplugged? Thanks for any help!!!
 
You can not leave it unplugged.

What does it do if you start it with the TPS disconnected?

Try that cold and hot, and then again with the TPS connected and report back. See my reply to your earlier post on the IAT air temp sensor in the intake manifold.
 
Swap/replace the ASD relay.
 
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