This is a B6 model 1.8t. Not sure what this part is, but I can hear a huge air leak coming out of it at idle:

It's on the top left side (passenger) of the engine bay

 

That is a check valve. You can pick them up from sites online pretty cheap. I can't remember the site I got mine from off-hand, but it was recommended by another member here. They were abouut $2.00 a piece if I remember correctly.

There are 6 or 6 of them throughout the motor, and they are notorious for drying out and cracking.

 

Thanks for the reply? Any idea on if it's simple to replace?

 

Yea, it takes about 30 seconds to change each one. I wish I could find the site I got them from, because they were cheap enough that I bought about 12 of them (just to have them as a backup). Its just a matter of pulling the hoses off the old ones and putting the new one in its place.

 

us plastic corp. cant remember which ones I bought

 

Cool, thanks a lot for the help.