Could someone explain the F-hose to me (where it is and that sort of thing).

Thanks for the assist

 

looking at the engine...left side...under intake y pipe...hose looks like an f....pointing down....for breather/vaccuum system...either one...not sure...

 

Here's a picture that showsthe f-hose location:

http://forums.audiworld.com/s4/msgs/2633854.phtml

It's function is to provide a common intake vacuum source (the top leg of the f) to both the crankcase ventilation system (the middle leg of the f that disappears under the intake manifold) and to the evaporative emissions system. I believe it only appeared on '00 and '01 2.7T manual transmission cars.