RPM drop when stopping

I have a 1994 Chrysler LHS 3.5 V6 engine and when I go to stop at a stop light or sign the RPMs drop to 500 and sounds like the engine is going to die. What would be causing this? Any help is thankfully taken. PLEASE HELP ME WITH THIS.

Okay now I have a new part of this problem. I took the car for a long drive and when the engine was at operating temp. and I stopped the engine died. What would cause all of this ... low RPM at stop before operating temp. and then dieing at stop when operating temp. has been reached.

Check air filter. Check throttle cables. Check spark plug wires, a weak wire will cause it to lope at idle. Another odd thing I ran into was when my power assist for my brakes started going out it would do that.