Losing power! help!

I have a 96 passat tdi wagon. under acceleration on the highway, i suddenly lose power. the engine sounds fine, and i do not lose rpms. but have the pedal on the floor, 4th gear... and cant even hit 60? but then if i turn off the ignition, and start the engine again it is fine again. its almost like i am running out of gas? could it be my fuel filter?

N75 Boost control valve could be the problem.
Look on the firewall for the electrical valve with the red, black and blue hoses. Check all the three hoses for breaks or leaks.
If no hose damage, then buy a new valve. Ensure that you replace hoses to original location.
Other problem could be a sticking wastegate.
Go to A3 forum and use search function for the forum and put in "limp" or "overboost.
Good luck,

You also have a hose (3" or so) inside the ecu - and it may be that one. Most likely the hose going to the ecu - lots of wear on where it goes through the frame.