I searched the forum and found nothing quite similar - which concerns me, but since everything else that I have dealt with before on this car was resolved through consulting fellow a3 owners, here goes...

car has been running fine for 19K miles. Just finished a trip to and from LA this last weekend.

Here's the situation: this morning, 5 minutes after the car was started, I was getting off the freeway and as I decelerated, I hear a loud hum from the back of the car. the hum changed in sync with the slowing down of the car - as it slowed down, the pitch of the hum got lower.

on my way home from work, immediately at startup, that hum sound returned. A bit apparent at acceleration, but definitely there when slowing down. I originally thought it came from the rear right side but I think it was simply due to my head and ears being on the left side of the car. when I turned my head, it sounded like it could have come from anywhere in the back of the car.

The performance may be a bit lagging on the car, but I also took it easy on the way home so I am not quite sure on that...and avoided hills, which is no easy feat in San Francisco.

Thanks in advance to anyone who reads this and can help. Car is still under warrantee but I'd like to go in to the dealer prepared if that's what's called for.

--David

 

Sounds like you may have a grabing brake pad thats not letting go. If not your fuel pump could be going out it is in a place it sounds like its right behind you. I had a fuel pump go out and it made an odd humming noise. but deffinatly a job for the dealer.

 

A strange hum that changes pitch when you slow down or speed up..?
Sounds to me more like its a wheel bearing......

 

thanks for your ideas. I brought it in for service this morning... will post the findings later on.

 

solved!

answer: loose left rear wheel bearing.

thanks for playing!