1991 Buick Century stalling

Can anyone help. My son has a 1991 Buick Century. The car doesn't want to start. Once he gets it going, it stalls while idling or at very slow speeds. Once he gets going down the road, it is fine but anytime he slows down it dies.

Clean the throttle body and the idle air control motor. It is probably dirty. That is why it wants to stall out while at idle and runs fine at speed.