Erratic Idle

[Rod_Lei]

So I changed out a bunch of sensors on my 88 5.7 350 and got the engine to idle way down. For like a week it ran very well, AutoIdle worked in the mornings, got nice and low once it got warm. Well recently, I've had this spontaneous Idle change everytime I drive the truck.

I'll start it up, it will idle up, hit operating temp, then come down to normal idle. Well I'll be driving for a little, and suddenly the idle will go way up and stay up no matter what I do. But. If I turn the truck off and start it back up, it will be ok for a while.

Does anybody have any idea what would cause it to jump up the idle like that? when it has high idle, it runs normally just like it would when it is cold, I think it's a sensor, but I don't know which one would cause such a high jump. Any help would be awesome!