I have a 1992 f150 5.0 with a 5 speed manual transmission. I’ve had and problem with the truck dying at idle for a long time now and even made a post already trying to fix it. I did all the common diag tests recommend in the original and didn’t fix or find anything out of the ordinary. I assumed it was going to just be one of those mysteries that never gets solved. Well recently I got bored and started tinkering again and found a couple unusual things. First off the contacts on the distributor cap seem to corrode and wear away extremely fast. Second is when I first start the truck it runs good and sounds healthy after cleaning the contacts. It always immediately fires up about the first crank and is good to go until it starts warming up. That’s when the problems begin. If I let it set and idle to warm up it begins missing out slightly. You can really only hear it in the exhaust. Then the truck tries to die and stumble. Second is I noticed that if I hold my hand over the ICM as soon as I start it I can feel it warm up. Not much but enough that it’s noticeable after only a second or two. Is that normal? Just to clarify everything I said happened before and after I cleaned the contacts. Any input it appreciated. I can link in the old post for anyone that would like as well.

 

The first thing I would do is clean the IAC valve.

 

IAC has been replaced and cleaned with an old motorcraft part.

https://www.ford-trucks.com/forums/1...high-idle.html
the link is for the old thread explaining everything I’ve already done chasing this problem.