did you ever consider your injectors shorting out, that is a major cause in alot of cars, because the injectors in old cars fire all at once so if one is not working then they all will not work, that is what happened in my friends late 80s buick. just unplug them one at a time the car can run on 3 cylinders! and also check the difference in oms (resistence) between them if the resistance is higher then the thing is burnt out. and if anyone needs someone that can solder parts I can sure do it just give me a few bucks i dont want much