93 3.1L Stalls and won't start when warm.

I have a 93 cavalier with a 3.1L mpfi V6. The car starts fine if it is cold but once it warms up it stalls and then won't start for another 20-30 minutes.

I pulled a code off of the ecm for the EGR valve. I checked it and the digital EGR valve was unplugged. I plugged it back in and that seemed to solve the problem. However the next morning the car did the exact same thing. No other codes were on the ecm. Does anyone have any ideas?

:screwy: IAC motor?