The idle air control valves on our cars, assuming you have a 2.5L, aren't that great. To be honest mine has Idled better with it unplugged and idle screw adjusted than it did when I had a working IAC valve.
.l..o_0..l. 93 MX6 LS KLZE w/ Interprep valve srpings and DE retainers, SS headers, Cat delete, Pacesetter catback exhaust, 11lb Flywheel, and Vogtland sport springs around KYB GR2 Struts.
Car set for over a year and someone stole the CAI, nice of them. Just replaced very noisy friction gear springs http://www.youtube.com/watch?v=OWeBUmLmAOM . Next project is to program a micro controller to convert GM MAF signal to a 0-7v signal that mimics our VAFs.
It's probably just air in the cooling system which was introduced when you swapped in the new throttle body. There are coolant hoses that get connected to the throttle body correct? Purge the air from the cooling system. Do a search if you're unsure how to do it.