Turbo underboost on Audi — on 2.0 TFSI it's PCV/diverter valve, on 2.0/3.0 TDI it's the VGT actuator or charge pipe leaks.
Bob's Mechanical Repairs — independent family-run garage in Birnam, Dunkeld, Perthshire. Call 01350 727 276 or email [email protected].