I am having problems with my car idling while in drive at a complete stop.

What is your question?

My car starts, runs, and shifts fine. But when I come to a complete stop while in gear the engine sputters and eventually shuts off. The problem first occurred when I was low on coolant so I thought it was a problem with the radiator, but I replaced the radiator and it now longer gets low on coolant; I also checked the transmission fluid level and there was no problems there.