Audi A6 Avant 2002

[McFsC]

Hi,

I've just bought a 1.9tdi A6 Avant 2002 with 120,000 miles on the clock. First few weeks it was running perfectly, really smooth etc. Now the turbo doesn't kick in until 2,200+ rpm, at first it was more like 1,800rpm. It's so annoying not having that bit of umphh pulling from junctions etc. Then earlier on the turbo wouldn't kick in at all but I could still rev high, just no boost. Turned the car off and back on and it was back, albeit at 2,200 rpm again.

Does this side like sticky vanes in the turbo or something more serious?

Thanks.