i have rebuilt a series 2 erst done about 3000 miles since. now when i try to accelerate the boost drops to 5psi on the gauge but it seems like the brakes have been slammed on. and it splutters. if u r on a hill it is worse. it has stage 1 chip stage 1 hybrid collins-31actuator 4"magnex k&n running 16psi (was anyway) any help would be greatfully appreciated. is it possible it is the ammel valve or metering unit?