Stalling after the engine is warm

[Bad89stang]

I have a 5 speed 89 coupe that runs great when it is cold. After the temperatrue goes up to operating range it has bad idle problems. If I am driving at a constant speed for awhile and then come to a light... I usually push in the clutch and hit the brakes. This is when the motor will die. If I wait until the last minute to push in the clutch(almost stopped) then it will not stall. I get some surging from time to time if the engine is warm.
I have already checked the TPS and it measured .98
I have cleaned the IAC several times and even tried another one(used). I did reset the computer after switching out the IAC.
This is really getting old. Should I just go buy another IAC and try it? Any ideas?