When the car is cold, it will idle GREAT.
Once she warms up, it won't hold an idle at ALL. YOu have to keep accelerator pressed down to keep it running.

I've replaced the IAC, and the IDLE control valve under the TB. No codes at all. What gives?

 

hmm good question, i was going to say check the fast idle valve, then see what codes if it is throwing nay out. there might be some gunk built up in the fuel injectors thaT MIGHT BE CAUSEING it to not idle. at cold temp, the car has a constant flow of gas , but when it warms up if theres gunk in the injectors it might be preventing a consistant flow of gas.