The 1984 may have the timing tang hole on the side of the injection pump. If so your checking the injections pumps timing chore is easy. If no port then drip timing the pump as at least a check is in order from your description. Methods of doing both are in the archives as it is a frequent subject on site.

For what we are talking about this symptom must have been present all the time since you purchased this car. If so it does sound like there is a good chance there is a timing issue with that pump.