Well the other day we put on a new TPS cause mine was shot, so we put it on.. set it to .54v... we set it WOT and it read like 3.80v.. then we released and it goes back to .54.. long story short, when we start the car it just goes insanily high with closed throttle, so we go to take it off, and the torx screw binds up inside the thread and snaps off about 4cm still inside the thread.. we went to a hardware store to find a tap to rethread it and get that sucker out.. but they had no screws/taps that was the same size of that damn screw... is it an odd strict GM produced screw? if so, how the hell am i going to get out the bolt still in there, and rethread it so i can put a new TPS on there? Please im in dire need of help, if you have any ideas, long shot or stupid, doesnt matter, i could really use some help. I appreciate anyone who considers helping, thanks so much.

Put this in 2 different sections considering its part of the TPI and its on the engine, sorry if I messed up mods.

 

Metric...

 

Yeah, it's metric, but even more bastard than that. It is an odd size, 4.5mm. The good news, it is an aluminum screw. Remove the throttle body & drill out the broken screw. Redrill both holes to the next size up American thread machine screw & tap to the new size. I THINK it is 10-32. All this is commonly available at hardware stores.
FJK

 

As for your original problem, you may have way too much idle air around the throttle plates. Reset the minimum air position, then set the TPS.

Wooooo-Taaahhhh.... (I just like saying that - sounds nasty.)