What causes the car to want to die/or shut off?

could it be the alternator or water pump by any chance? Any way of checking those to see if that could be the problem?

I will offer a guess; vacuum leak(s). Check the pcv system! Clean the throttle body and plate (butterfly).

No battery problems, loss of coolant or overheating. Starts up fine & drives good. Only when going slow or coming to a stop it acts as if wanting to shut off or just dies if don't keep revved up. Could spark plugs have anything to do with it? Or something else?

Go back to pushrods second response.