Croaking noise coming from engine (Passenger/Driver)... listen to sound clip
 

I have a weird noise coming from the Passenger and sometimes from the drivers side of the car. It seems like it's coming from the engine, not the suspension. I have tried to bounce the car by pushing on it to reproduce the noise, but it does not come up; which is why I do not think it is the suspension.

Here is a link to the sound clip of the noise:
<a href="http://sdcc17.ucsd.edu/~bhemraja/a4_noise.mp3">a4 weird sound</a>

Sorry for the wind noise, that's the best recording I got. It happens at 4sec, and at 14sec.
It happens when accelerating from a stop usually about 50% of the time, mostly during acceleration from 1,000-3,000rpm. Sometimes it can be heard twice, once at 1,000rpm, and once at 3,000. However, when the car is in neutral and cruising at these speeds, no noise.

2001 A4 1.8TQMS 43k miles

Any idea what this thing is??????
It's bothering the crap out of me, just bought the car and the dealership claims they don't hear anything... I might take it in again for this same noise.

Thanks.

--bhishan

sounds similar to my cam chain tensioner when it was failing
 

Try to reproduce it by opening the hood and driving slowly accelerating in 1st 1000-2000rpm range with someone listening trying to pinpoint it outside. If its the cam chain tensioner the sound is comming from the back of the engine head.