1989 Plymouth Colt Stalls at stops

My car dies when you stop (such as at red lights). This is usually only when it's just been started. The problem will persist when the engine has run for about 15 minutes if I run the defroster or air conditioning. If its rainy the problem tends to persist. Especially in mist. It has a new fuel pump, fuel filter, distributer cap and roder. At this point I'm at a loss. It's not giving any codes or check engine lights. The only other issue is a lack of power under the conditions that make it stall.