hey i have a 00 a3 tdi. lately when i accelerate hard it causes the car to go dead as if no boost from the turbo. it happens arround 3500 rpm. once i switch off the car and start again power is back to normal.. i heard it was a problem with the air flow sensor, just beside the air filter, so i changed that but ave same problem. is there any other sensor/meters that could be at fault or any ideas wat the problem might be.