Had the injector refrubed on the 55 a4 2.0tdi s line as it was shaking really hard on idle and juddering under load. Came up as cylinder 4 misfire. The injector was tested and now has been reconditioned and the shaking has gone. HOWEVER!!! The car has no power what so ever. There is no excess smoke of any colour ocming out of the exhaust so dont think it can be turbo.. What do u guys think it is?