In a 2k Audi TT Quat, Driving down the interstate, about to pass a semi going uphill i downshift into 4th at 75mph, and there was no boost whatsoever, almost all the way up to 6.5k rpmwhen i let off the gas. once i got back onto a flat stretch of road i tried to see if id get boost response and the engine waited all the way until i got to 4.5 to 4.7k rpm to even begin to spool. And once i stopped for fuel i was getting back onto an on-ramp where ibeganto accelerateand the boost spooled regularly up until about 4k rpmthen it was like slamming into a wall or redlining very early, absolutely no boost at all. i dont even know where to start, the DV, N75, intercooler, plugs, and coils are new. and when i got home recently i listened intently to hear any kind of air leak, and looked over all the hoses for cracks or wear. i am lost.

 

Any CEL? Can you check for stored codes?

My guess would be a boost leak. Since it can build boost, check the N75 & DV first.

It might be something as easy as a vacuum hose leak on the DV & N75.

 

Is the car smoking at all out of the tailpipe?

 

well recently i just got a CEL but i have no way to read the code, i need to find a cheap VAG com, any ideas on where to find a "less spendy" but efficient CEL reader? and its not smoking other than the common cold weather + hot exhaust smoke, also i bought the forge 007 and i put the green spring in it, and there are no leaky hoses on it. and the n75 was replaced recentlydue to this problem and no luck,and all those hoses are air tight as well. hopefully when i get the vag com it will tell me something useful. thanks.