New battery, new alternator and car stalls at idle. What could it be?

DIrty IDLE AIR CONTROL VALVE. Find it, clean it. CLean the throttle body, too Use Gum-out and Amsoil Foaming Cleaner, if you can find it. ALso, replace the factory junk plugs with Bosch Platinum or Fusion plugs. You will get more power with A/C on than you had with A/C off!!!