I've had this issue since I've bought my Golf. It is a 1.9 TDI 105bhp and the modifications are 18" alloy wheels, Piper exhaust and induction kit. I can always hear high pitch whining noise when driving normal. When stepping off the accelerator, it makes a whoosh noise which I think its due to induction kit. The main problem is the car feels so slow that I struggle to set off from stationary such as traffic lights because the car feels jerky and seems to be losing power and at the same time I can see huge cloud of black smoke. I had it checked from garage and they found one of the boost pipe had come off so the reconnected it back and I haven't noticed any improvement in the performance. It still drives slow but the smoke is blue instead of black. The blue smoke also comes out from exhaust every time I start the car up. Now I feel my boost pipe has come off again as the smoke is black again. Apart from a new boost pipe, what can I do to stop this whining noise and restore the engine power?