Okay I need to get this problem figured out asap because I need my truck and I don't wanna pay a shop to fix it if it ends up being something simple. So I parked my truck in the barn 2 days ago and everything on it ran fine then I fired it up earlier this afternoon and the idle speed has dropped from 700-800 to around 500. I put it in 1st and drove it out of the barn onto some grass to wash it and the tuck ran fine, it didn't blow any excessive smoke of any kind, and it didn't throw a code to light up a problem light on my dash. As soon as I pushed the clutch in and took my foot off the accelerator it dropped to 500 rpm again. Now I thought I could just turn up the idle speed with that screw I have on my injector pump but part of me isn't sure if that's my problem or not. If it was the screw that vibrarted itself out (I don't know how else it would change speed) I would think that is something that would happen over time and not over night. Does anyone have any idea what it could be? It also might be worth noting that if I just slightly tap the accelerator then my idle speed jumps up to where it should be (750-800 rpm). Anyone have an ideas? My truck is a '97 12 valve, with a 5 speed if that matters any.