right ive just fitted a 4x4 inlet plenum fuel rail and pressure reg to my 2wd saff but used the 2wd throttle body etc (dont know if different)

The car runs fine but has got what seems like an air leak now, sort of like a loud whistle it goes away when you rev the car.

i even removed the full thing and put more new gaskets on but still the same

can anybody shed any light please