Audi a4 tfsi b8 no power

[Jay bagnalll]

 

got a Audi a4 b8 tfsi 2009. Running around 330bhp

The car isn’t boosting properly wouldn’t say it’s in limp mode but kind of is as it’s really down on power, no codes or engine lights.

No split pipes, turbo fairly new. Tried changing map sensor no luck, tried new diverter valve, tried n75 valve. 

And other suggestions as I really can’t get my head around it and want to enjoy driving the car again.