Symptoms:
-cranking the engine 20-40 seconds then good idle.
-revving the engine it'll misfire and stall.
-drivable with constant light pressure on the accelerator & left foot braking
-cruising is fine but will stall accelerating from stop.

Problem:
-loose fittings in distributor cap.

Fix:
-replace distributor cap.

 

divide your subject into 3 parts. first the fuel system, second the electrical system and third the mechanical system. go check one department at a time, there is no short cut if you one to get the best and proper way to address the issue. i would suggest sending the car for a tune up first since its an old car and you might have no idea how it was maintained by the previous owner. better safe than sorry. Like spending on the two items i suppose would have wasted resources if they were not the culprit and besides if fuel pump is damaged you would not even have a chance to properly start the car, while for the fuel filter, its not at all a waste but necessary even for a good running vehicle, its called preventive maintenance.