Just finished replacing the head gaskets, got the truck back together, fired it up and once it caught it revved to 4 grand right off the bat, which i was trying to avoid given that my handy work was untested. i adjusted the cables, i figured that the retaining nut got moved during surgery. once they were adjusted back to were they should be i started it back up and it idled fine. once it was warm i gave it a rev and it stayed there, i gave the gas pedal a quick little tap and it dropped back down to idle. Is it just a matter of lubrication? i wouldn't be nervous to do that if i had not just finished the head gasket job, there are just a lot of variables i want to make sure i did not overlook something else first. also maybe totally unrelated but there is a vibration/buzz noise coming from the instrument cowl when the ignition is on both with and without the engine running. it might have been like that for a long time but i am super vigilant tracking down noises right now.

 

Sounds like the throttle is getting hung up mechanically. Find a picture on the inter-web or RAVE and Double check your work against it.

 

What about the ICV. Idle control valve. Anyway that's not installed properly? Loose or damaged connection?

 

Try disconnecting the cable form the throttle body to see what is hanging up.