2002 Chevy Cavalier Low idle

Engine Mechanical problem
2002 Chevy Cavalier 4 cyl Two Wheel Drive Automatic

I have a 2002 cavalier with a ecotech motor and automatic transmision. The car idle's low and when I slow down or come to a stop it goes to shut off. Also if I turn on the heat, radio, or anything else on in the car it will automaticly shut off. The only time I can run these things is if I am on the highway