Engine or trans? That is the question....

[WillCherokee]

I have a 91 XJ 4.0 AW4 181K and going but, I have a situation that's driving me insane. So...it runs amazing after the assembly but when I drive and coming to a stop like a red light, it starts to bog down to like 250rpms...almost cuts off. Hell, it actually cut off a couple times this week. When I do stop and it stays running, I can feel it jump and the rpms start to rise like the transmission downshifted to take off again....what do you think it is?

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[4.3LXJ]

The first thing I would look at is the idle air controller on the throttle body. They can get dirty and sticky inside. Easy and cheap to clean

[cantab27]

yep TPS......................

[Pinkyman]

I am having a similar issue since i "cleaned" my IAC, it doesnt want to start, and once i get it started, i can keep it running if im on the gas, but it dies as soon as i let off. I cleaned it again, and it would idle fine, and almost die when i let off.

Ive been reading about it all day, since it worked before i cleaned it, and it sounds like you can clean it and reset the computer by disconnecting the battery. Then it can re-learn where it is supposed to be.

[denverd1]

its an engine problem. good suggestions above

[WillCherokee]

Ok

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