Anyone have any ideas why my 1986 Cad Deville. Will seem to be running fine and then just stall out. Seems to happen when decelerating. Help

 

You lack details. Codes, is engine hot or cold, how long does it take to happen, how much fuel in tank, does it restart easily or does have to sit? Tools to diagnose spark tester, fuel pressure gauge, voltmeter, and test light? Car has OBD so no scanner required. Look in FAQ for OBD