Ford Repair: bearly runs after reaching opperating temp, fuel system, ecm

Question
302cid runs great when cold. once opp.temp is reached eng. misses and backfires. if you just feather gas pedal will run smooth. try to add power and starts missing and backfires. changed coil,and ecm?(bolted onto the distributor)any clue?

Answer
Donald, if you have changed the coil, then I would go ahead and finish off the tune up with plugs, wires, cap and rotor.  If you have done all this, then I would look to the fuel system.  I will say this, it sounds very much like the coil.  I hope this helps,   Jason