I have a 72 f-100 with the engine out of a mid 70s mustang, i think. trouble is after 5 miles truck dies out it starts again but this continues till the engine cools down, i have a new eldebrock 4 barrel carb, new high output coil. new plugs, wires and points. new fuel pump and filter with a fuel pressure gauge, putting out 5 psi to the carb. any gussess