Why does my car stall everytime I come to a idle stop at a light? on 1990 Chevrolet Corsica

The idle fluctuates up and down it also stalled and would not stay running if put in gear

Asked by for the 1990 Chevrolet Corsica
It could be many things, unfortunately and without experiencing the problem first hand or being able to do some basic diagnostic tests its hard to say. It could be a vacuum leak, an idle speed control problem, leaking EGR valve, poor electrical connections, many things is the check engine light on ?
the check engine light is not on and I replaced the throttle positioning sensor last night and it still stalled on me after that was replaced.