Re: 1989 v6 200
Other things that come to mind are a faulty fuel pump itself, as your manual pumping action is replacing the job of the pump, keeping her running.
As Tash stated, check to ensure that the tank vent is clear, and also check the anti syphon valve, they are notorious for sticking in a semi closed position. Knock the guts out of it to see if this is the problem.