A few months back I was taking my TB apart to coat it. A bolt on the TPS broke, two on the top plate broke and all four of the butterfly screws broke. I took it to a machine shop and had the broken parts removed and the holes tapped. When I put the TB back on it was having problems sticking around 15-1800rpm at idle. If I would blip the throttle it would return to a normal idle. It would almost always stick after giving it a slight amount of gas and I'd have to blip it again. I figured that the guy possibly put a butterfly back in slightly off and it was hanging up or something along that line. I decided today that I would take it off and give it a good look inside to see if I could find out what exactly is sticking. I took the linkage cover off, fired it up and moved the linkage a little bit. It wouldn't return fully to the stop screw. If I moved it alot it would return all of the way back to the screw. I shut the car off while it was in the "stuck" position. When I shut the car down the linkage went back against the screw. I though it was strange. With the car off I moved the linkage and it wouldn't stick any of the 30+ times I tried it. Fired the car up and move the linkage slightly. It sticks! I shut the car off and it returns to the screw. Basically it only sticks with the car running. When the car shuts down it returns to the fully closed position. WTH is going on here? Why would it only stick w/ the car running and then close just as the car was shut down? I couldn't get it to stick once w/ the car off and I TRIED!
Any ideas?
TIA