I originally posted this in the A4 specific forum, but was unable to get a fix on this sound. I figured I would give the general tech area a try.

A little while ago I posted about a strange sound I was having when I would release the accelerator. I used my phone and got a poor quality .wav.

I placed a sound clip on the sights n sounds forum

https://www.audiforums.com/m_722278/tm.htm

Thanks in advance.

2001 A4 1.8T QT 80k. no codes and boosting normal.

 

hmmmm sounds like a blade catching a fan belt or the serpentine belt is fitted incorrectly like the V lines are not lined up and a few out ( out of alignment ), I did that once and noticed the belt was out of line with the rotors

 

I would check the vacuum line to the diverter valve. It sounds like its not opening or fluttering the sound clip is not very good. Does it do it all the time when decelerating or just after the car is under boost.

 

TheAudiTech: you got a PM...thanks