Car has been stalling while idling at stoplights.

Car has been stalling while idling at stoplights/signs. It stalled first time, tried to restart took 5 mins got it going again. Other two times immidiately started again. Tried 'heet' in full tank of gas (it is below zero temps during all of these times, however, my car has a remote start and I do start it for 20 mins before leaving the house, it does sit outside at night). Tank first time was at 1/4-1/2 full, second and third 1/2 to full tank of gas (with heet both 2nd and 3rd time). So heet is not answer. Wish it was that easy. Any ideas what it could be? The rpms go super low at lights, and today felt like it was going to stall again at a stoplight so I two-peddled it (which I don't like at all) to keep rpms up and keep it from stalling. Please help!