i have been having similar problems with my 88 2.9, it will run and drive just fine but eventually it will die as if it ran out of gas. after searching around we found hot water on the inertia switch most likely coming from the heater core, so far i've spliced the two wires togeather but haven't had a chance to test it. as for the switch when i get a JY one does it matter if it is a Ford 2.9 or can it be any ford switch?