06 Jetta TDI hissing during acceleration

I have a 2006 VW Jetta TDI, 1.9L, 5-speed. Hearing a hissing noise when I accelerate, in all gears. Hissing will last about 3 to 5 seconds then stop, especially at higher gears, when I’ve had my foot on the accelerator for a longer time in-between gear changes. Any ideas?

Turbo waste gate opening??

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