Ford Repair: rough running 302, 1976 cobra ii, manual 4 spd, intake manifold gasket, cobra ii

Question
car runs rough when accelerating too fast.  it seems to run worse after it warms up.  I am the second owner with no other repairs done to car. it has 36,000 miles on it roughly.  I replaced the pick up coil, coil, rotor, distributor cap, plug wires, gas filter, had the "computer" module tested and it tested ok, also checked the timing,  plugs are relatively new(replaced in 1994 with porclain ones, have about 12,000 miles on them).  still runs rough with an occasional backfire when down shift and or accelerating too fast.  Did run out of gas(my gauge is not working) a few weeks ago but it was like this before that happened.  It almost seems like it is not getting enough fuel or it is like a bad tank of gas.  did empty out that tank of gas and new fuel put in.  What do you think???????

Answer
Dan,

Backfiring is usually due to the timing being out or your carbuerator out of adjustment. I would also check for a vacuum leak-check all the hoses and the intake manifold gasket (to do this spray carb cleaner at the base of the intake manifold and the base of your carb-if you have one- and if it revvs up, you have an intake manifold gasket leak). Hope that this helps and if you need further assistance, please do not hesitate to contact me. Good luck.

Ken