Lots of things can cause that symptom. A vac line could be connected to the wrong thing for 1. The ash can could be chock full of ashes. The intake manifold could have a leak. The ignition switch behind the steering wheel could have a faulty wire, the battery terminal cables could be fried, the battery could be putting out 10 volts or less, there could be a bad solenoid or just plain loose wire touching another wire or crimped somewhere, or the alternator could be either going out, or the belt just has too much slack in it. The pin that opens the door to the carb could also be not opening it all the way, forgive me I forgot what that' part is called, lol Start with the cheapest of these problems to fix in order. For example the ignition switch is like $5 or less everywhere, although not everyone has the steering wheel tool.
