I have a 2002 WRX with a lot of aftermarket modifications. For the last couple of months my Turbo fades in and out when I'm really on it.. When I move quickly through the gears I have no problems but when Im pushing the turbo in 4th or 5th gear thats when the issue is very apparent. I put on a new fuel filter hoping that would help (cheapest solutions) and it didn't help much. I don't know if I need new fuel injectors or a new turbo? Someone also mentioned to me something about the pressure valve being plugged up.
I would appreciate some feedback if anyone has experienced something similar..