How much horsepower are you running? Where is the pump located(distance from tank)? What size lines in and out of the tank to the pump and from the pump to the engine? Filter arrangement? 1 before the pump and one after? Where is the fuel pressure regulator located(distance from fuel rail)? Are the fuel rails aftermarket or stock? Do you have a tuning program, hptuners, etc? If you do post up the log file and I will have a look. RC