I had the same problem on my 5.2 97 JGC Lim and had a hard time but here is what I did. Also I only noticed this problem when it got below 40F. I first pulled off the Throttle body and cleaned it all out. I cleaned the IAC Idle Air Control Sensor put it all back together and it worked at first for a few months. I started to have the stall problem later on and just bought the new $30 IAC and the car has been running problem free, i guess, since then. Good Luck.