Hesitation and Revs 09 A4 2.0
 

Hello I have a question regarding my 2009 A4 Avant. When I accelerate from a stop or at speed my engine /turbo or transmission feels jerky or clunky. Sometimes an outright banging sounds. Also the revs stay high after I accelerate and don't come down and respond normally when I lift my foot off the pedal.
Please advise if you know this problem.
Regards,
J