The OP has stated new pick-up, tank, pump, EFI hose tank to line. Was the strainer new with the pick-up assy.??
If the float or needle is sticking, the carb will run dry, and the engine heat will cause a large vapor bubble that will stay trapped until conditions change. The old school way
to check is to tap on the carb body somewhere relatively harmless with a plastic screwdriver handle to see if it frees up, while the car is running poorly & before it quits
running completely.
