i brought my a4 a month ago now. when i first took it down the motorway i had a hell of alot of black smoke coming from the exhaust and a short loss of power. after posting on here i was told to do a number of checks including cleaning the erg. this has eased up the problem alot but i still get the odd cloud and a loss of power when giving the car a bit of a blast i have noticed though that when the car is abit low on diesel it does not seem to do it as much. any idea on this or what else i could do to be rid of this.