What could be the problem if i'm hearing a pretty distinct buzzing sound while i'm driving that seems to be coming from the back passenger side wheel in my 01 a4 1.8t. It seems like ever since the snowhas gone, my a4, out of nowhere, started giving me problems. First i noticed the fiberglass shield on the bottum of the car is missing (fell off in snow somewhere this winter). Second, i got an oil change and while driving it home, i had no boost at all. I checked the wires and found a whole through the vacuume hose that runs into a checkvalve right by the intake. The check valve also had a whole in it. I just replaced the hose and check valve and still didnt get all my boost, just a little. The the next day i bought and installed a forge dv which, i think, did the trick. I have no way of telling if i got all my boost back, but i think i have most of it. All this happend within the last 1.5 weeks. During this period my check engine light has been on and turned on right before the oil change. I did the battery reset and turned it off until it came back on 20 miles later. The car seems like its running fine except for the back wheel noise. I finally ordered a vag which is coming this week. I hope i can understand how to use it and find out what is wrong. In lancaster, PA, the audi dealership charges somewhere around $130 to work on audi's, thats why i want to figure out and fix these problems on my own. Let me know what you guys think and if anybody has a chip they want to sell, let me know.

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The buzzing is your wheel bearing, best way to see which one is lift the car off the ground grab and jigle the wheel at the 9 and 3 and 12 and 6 positions, the wheel with playis usually the one with the bad bearing, i ordered a bearing off a site called blauparts for about 60 bucks shipped, i had another bearing replaced for 175 labor and the bearing , made by ***, cost me about $30