Cleaned the IAB valve, now have 'sticking' throttle

[Ford Vader]

Hey guys. I was having a problem with my car occasionally stalling when I would come to an idle, its a stock '90 GT 5 spd. I tracked the problem down to the IAB valve so I removed it and cleaned it out thoroughly with carb cleaner. While I was at it I removed the throttle body and cleaned it and the egr spacer out. When I started the car I could tell immediately that there was a difference, the stalling problem is definately gone. But now the car idles higher (about 1000 up from 600) and when I rev the engine and let off of the gas and push in the clutch the rpm's don't fall back down right away, the rpm's drop slowly to about 1500 rpm and hang there for a little while, then finally come back down to about 1000 rpm. I checked for vaccum leaks and there are none. To test it I unplugged the IAB valve and ran the engine for a minute. It ran fine with the IAB valve unplugged, it idled around 600 - 700 rpm and the rpm's would drop immediately after letting off of the gas, so I know the problem is with the IAB valve. Should I just get a new one? I wanted to get some opinions on this before I got out and get one because they're $80 or $90. Is there anything else I should check? Thanks in advance for your help!