First off is it a throttle body or Multi-port injection. put a fuel
gauge on it and check the pressure. throttle body injection should take
4-9 psi to start. multi port will have the injectors (one for each
cylinder) in the intake. That system needs like 35-45 psi to work. I
think you would have TBI on that system. check your connections to the
injector to make sure it is good if your pressures are good. Also make
sure that you check the ground connections near the battery and at the
terminals. Make sure that you have no green wires (corroded) by lightly
pulling on them to make them break. Don't yank them just pull lightly.
Ford had a big problem with corroded wiring back then. I fixxed many a
vehicle by replacing battery terminal ends and ground wires for
conditions like this. By your description I would look there first.