Is this normal

[mbronsell]

2000 S4 when pulling away from cold, light throttle there is a noticable hiss as if the car is dumping boost, it is also noticable when warm very light throttle at 30mph and you very lightly open throttle, other thing dont
know if it is connected very occasionally again at light load it just doesnt feel smooth. reading other posts wondered if it could be audi DV,s or N75, car has audi SH 100k no faults stored..thanks for any help

[Blue_Thunder]

Could be a boost leak. Get it pressure tested as there are plenty of places boost could be leaking.

Take it to a specialist and get it health checked. Defo doesn't sound right... unless you've got an uprated Bosch 044 fuel pump, the noisiest car component ever created!