Got an 03 A4 1.8t. Lightly chipped and no other modifications.
Heres the issue. Under acceleration I can hear a hiss from the engine compartment. No noticeable change in performance but sometimes when I come to an idle, its rough and I can hear a little hiss. I get out.. pop the hood and identify the source of the his... and give it a thump. The valve snaps itself together, the hiss goes away and the idle returns to normal. What valve is this? Does it normally snap apart like its doing? If I removed it from its assembly I believe it would just fall apart. Is that normal?
Jake