Can someone tell me what part this is?
 

Can someone tell me what part this is and what part to order? Starting to go bad and make a whistling sound.

Its the hose underneath these 2 cables

Here is the photo

This car is starting to drive me nuts.

1998 318ti

Just had an exhaust gasket replaced and inspected. First drive with it back and now I have shaking, loudness and vibrations. Guessing another part of the exhaust went bad. Ugh. While looking around I heard this hose making noise and figured I better fix this as well.

Any help would be greatly appreciated.

Looks like it should be here http://www.etkbmw.com/bmw/EN/search/...CE/13/13_1721/
FCP Euro has been very helpful helping me track down parts. I've ordered from them a couple times and have been happy with their service. Good luck!

Are you referring to the rubber elbow connected to the secondary throttle body or the hose connected to the plastic tee going into the elbow?

I believe eeuroparts calls it a fuel hose it runs to a vacuum tree that connects to the injectors