I just recently changed out my fuel injectors and also cleaned the air intake and the throttle body. During this process I have accidentally unplugged what seems to be a vacuum line. I can not find where it plugs into. It has a double barbed plastic connection piece that looks like it plugs right into a hose of the same size but yet I can't find it anywhere.

Car is an 99' Audi A6 Quattro sedan.

Here's some pics :

The skinny hose that runs alongside the larger coolant hose and under the coolant reservoir is the one that confuses me.

You can see here the barbed connector sticking out of the culprit hose.

This guy!

Please help! My car will not run with this hose unplugged...a bit of a newbie here. Any help is much appreciated! I have been struggling with this for over a day now and NEED my car! Thanks - Josh

 

That looks like the line that runs from the vacuum solenoid to the vacuum reservoir. It looks like some replace the factory line with store bought vacuum line. (That's okay, mine is the same way.) Anyways, the end that you are holding up should connect to a 3 way connector near the vacuum solenoid. (Except your connector looks inline...) You should have a vacuum diagram sticker on the underside of the hood.