OK, so the car has, for the past week, been stalling like clockwork every time i start the car. I changed oil today, so while i was out there, i took off the throttle body and IAC valve, cleaned them both, and reinstalled. While i was cleaning the IAC, i pushed a part of it out of the way (inside, w/o disassembling) that pretty much opened the valve entirely. There was no spring back of the mechanism. Anyway, once i got the everything put back together, i started the car. it started fine, but immediately shot up to around 2500 rpm, then settled in at around 3000. I tried turning the idle set screw on the TB, but it changed nothing. I quit after this and had a beer. . .too much car thinking for one day, and one of the roommates can drive tomorrow.

I have two ideas as to what went wrong:
1) being tired and hungover, i accidentally knocked off a vacuum line on the intake after the TB. It's sucking air like crazy, and the idle is going up. This is the easy solution.

2) My IAC valve is broken, and was broken before, causing the stalling. Previously, it had failed in a semi-closed position. When i took it off and cleaned it, I changed it to the "open all the way" position. The engine is getting a huge amount of air, thus the high idle.

All that being said, how to I check/diagnose the IAC valve. I read somewhere about a procedure to set the idle speed by shorting a connection somewhere. Any ideas? I have a spare IAC valve from a boneyard. . .any ideas on how to bench test it?

Is there something else I might have overlooked that could be causing this?