Vacuum connection mystery HELP!!

Hi I removed air box which is riddled with vacuum hoses, sensors ect. I have one connection for which I don't have clue where is connecting too. I have marked it on screenshot

 

Hi Frank.
What you are looking at is the One-Way valve for the Variable Air Intake system (Flapper).

That end of the One-Way valve would go to the main vaccum supply hose for the system from the intake vaccum at the throttle body. So look for a hose not connected under the air box into the throrttle body. Hopefully the attached diagram will help. You haven't mentioned wether you have a 5th or 6gen. Diagram is for a 5th gen, not much difference between the two with respect to the Variable Air Intake system.

Do you have the flapper system operational? If not the main vaccum supply hose feeding the One-Way valve MUST be blocked off.