Hi everyone I'm having trouble with my car. Ok il try and explain the best I can, it's an a3 bkd, it feels very slightly under powered, at idle I can hear a slight air hissing noise From the vacuum solenoid block (black box,6 pipes going to it) having someone blip the throttle I can hear a loud hissing noise that I have traced back to around the back of the engine (turbo area) if I unplug the solenoid box the noise stops, and while revving then quickly turning the engine off there is a chatter noise like a Dump valve (sounds like highly boosted jap cars do) from down the front of the vehicle. I really don't no we're to start. There's nothing obvious, have checked pipes ECT, my egr cooler has been removed and the nessasery things blocked off so that rules that out. Anyone come across this before?