E30 Zone

Can anyone tell me if the pipe circled in the picture is a breather pipe or does it go somewhere else the car has just recently been idling like a dog so i have changed the blue temp sensor but can't remember if this pipe went to anything it sucks quite a bit of air.
Cheers

[img=http://img218.imageshack.us/img218/7664 ... wq8.th.jpg]

Oh and by the way it still idles like a dog so any help would be appreciated.

Cheers