When the truck is cold there are no problems with the idle speed. After I drive home and park, the idle fluctuates from 500 to 900 rpms and keeps doing it every couple seconds.

Please God let this be a simple and cheap fix! This truck has been a pain in my *** since I bought it.

96 5.2L 2WD Auto Trans

Thanks,
Zac

 

replace throttle position sensor (TPS) on drivers side of throttle body. about $40-50 at any parts store.

 

Have you cleaned your throttle body and IAC recently? or ever?
If it's dirty in there, it'll cause idle issues.

Testing the throttle position sensor is a good idea too. Should be 1 volt with throttle closed and smoothly rise up to 3.5+ volts at wide open throttle.

spraying around the intake with carb cleaner would eliminate vacuum leaks as a possibility.

 

the surging idle problem is probably not testable by the rotation of the throttle. its something weird that the stupid thing does when its running and either hot or cold or wet or dry or feeling ornery. i think its some kind of electrical noise or ever so slight voltage surge.

just replace the stupid thing. if it fixes it, smash the old with a 3 pound hammer just for the satisfaction. that's what i did and it made me feel a lot better.

 

TPS, 37.00...
Go for it.