1.8t auq over boosting

[gary28482]

hey guys having a problem i first taught the car was dropping boost but since connecting a gauge i have seen its over boosting then falling back it is completely stock what happens is when im driving along if the car is around 2000rpm and a i plant the throttle the boost goes up to 14.5psi then when it hits about 2800rpm falls off to 7psi then back up to 8psi and stays there the car feels grand from then on but its quite annoying also i noticed a hissing from the right hand side of the car but i would think the boost would not stay high if it was leaking

[S1]

It can be from a whole host of reasons , mine was 3 different shorts in the wiring loom which lead to the destruction of the Turbo, through continious overboosting. None of the faults showed up on VAGCOM

[gary28482]

i have had 2 code flash up on vag come high idle and system bank lean 1

[HaNs]

Find the hissing and fix it, check lines to boost control solenoid

[S1]

crank sensor is always   a good place to start

[RogerB]

Check your hoses, clean the throttle body, get the throttle body aligned, try new N75.

When I had boost issues it was my N75. But as you have hissing, the above is a good starting point to make sure the common issues are eliminated from the investigation.