Vaccum line & Throttle body help needed

[DCmk3]

So I have a few questions, firstly, what does this thin line do? Or where does it go to?



Isn't this gap a little large when the throttle is closed?



And I hear a "rattle/knock" sound from the marked area when I tilt the throttle body from side to side as if something is loose inside..
I guess that's not normal? 

[Screech16v]

That vac line controls the flap for the freshair/recurculate  switch, has somebody tried port the throttle body  as it does look like a big gap around the butterfly ,does it have a fast idle?

[DCmk3]

So that's why the recirculate switch doesn't work.. someone managed to actually snap the little plastic thing which that pipe connects to at the firewall.. 

Unfortunately that picture makes the gap look extremely exaggerated compared to how it actually is.
If I hold it up in the light, I can see light around nearly the entire butterfly, but not enough to really see through.

I will try and get a better picture in the morning.


The idle is 900-950 on average, although on idle it seems to sound as if it has a cam, like a constant lumpy idle as the Mk3's usually do on warm-up.