Hello,
I just bought 2002 A4 1.8 automatic from a private person about 3 months ago, the car came with a boost guage which was cool. When I was driving on the highway the PSI dropped and cut off out of nowhere, then it went back on again, like nothing has happened.

Then later when i was driving to work going up hill the PSI dropped and cut off yet again, this was scarey because i was going uphill and I slowed down to a crawl. The car would start to boost then it would cut off, I made it up the hill after the turbo kept cutting off about 3 to 4 times. Then the check engine light came on.

Can someone help me out
Thank you in advance

 

sounds similar to what happened to me. i was told it was my waste-gate actuator.
is there a ratteling sound when you back off the throttle?
still need to get mine fixed

 

Could be that or could be diverter valve.