I have same noise on my 08 Mk5 1.9 tdi 105bhp. I can describe noise like woosh noise, first I thought it was when I change gears 2nd and 3rd, after I noticed that it is not gears it does it when you lift foot from accelerator pedal. It happens not all the time, I believe maybe its to do with weather/air cold/warm. As its mainly happens when is cold. I also been trough diagnostics, and all seems to be fine. I am kinder started giving up and live with it. Main concern was that turbo is giving up, but after doing quite bit research online, seems to be there are few cars out there with same problems. My car done just over 100k, few my mates got identical Mk5's with half mileage and having same issues.
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