My audi is 2002 model with 117k miles.This is the first time i have owned a diesel. a week after purchasing the car it would not accelerate above 80mph so the maf was replaced with a reconditioned one. This cured top end speed but did little for low level grunt. Occasionally, the car will take off in all gears and across the rev range and the power of this is exhilerating like being pushed along. Is this normal? Under ordainary driving the car requires lots of throttle and feels like it is underpowered. Am i asking for too much out of my audi?