Quoting SouthCaliVR4:
Check your base idle. the small screw head in a cavity on the throttle body. OE is a small black rubber plug covering the screw. Sounds like the idle was set cold & as the cold idle valve closes your idle drops off to stall.
This right here helped me. My car would idle about 500 rpm, and if I had my lights on with the heat blowing it would stall out on occasion. I let the car get to operating temperature, turned on every accessory possible, and adjusted the idle screw to 750 rpm. Now she's perfect without any stumbling.