I have an 89 F150 302 Just changed timing chain as it jumped a couple of teeth. Changed almost everything else plugs, wires distr cap, coil, starter relay and the ignition module. I just got the truck and was changing know fail parts as the older gentleman that hd it kept it in great condition but never changed plugs or anything. Well even before the timing chain issue what is happening is that when it is cold I will get to a stop and it will die out. After it warms up some the RPMs will flutter up to 100 degrees and then steady out. After it warms up it is good to go. Is this a symptom of the TPS going. I pulled codes and it had a history code for the TPS but not an active one. If so easy fix so no biggee just curious of this is what it may be.

Thanks all!

Andy

 

Sounds like the IAC valve isn't working properly. Try removing it and cleaning the inside with a Q-tip and alcohol, or brake cleaner or carb cleaner. Just be sure to not get it in the solenoid part of the valve or it could/will damage the electrical part of it. Could be that carbon/soot is keeping the valve from operating correctly.

 

X2 for the iac. Had an 89 that did that. Cleaned it with carb cleaner, was good for a while, then symptoms reappeared. Replaced and all was good. Cheers!