2001 Nissan Maxima ISC System

I am having problems with my car. When I am in the drive position with the air conditioning on and waiting at a stop light, my car runs smoothing and suddenly it seems like it loses power and wants to turn off. I have changed the ide speed control, I have changed the throttle body seal , all hoses and accessories have been checked and still having same problem. It does this also when I do not use the a/c. But mostly with the a/c on.

Any suggestions.