I have this tube in the engine bay. Looks like maybe a mouse had at it. Engine seems to run fine though.

I checked the PDF service guide but could not find it. Does anyone know what this is supposed to do?

 

Possibly the vacuum tube that connects between the intake control solenoid valve and intake manifold.

 

Yeah I think its the tube marked 48 in this diagram. I've replaced it as I had the front bumper off to install new headlamps. What is it that it is supposed to do?

 

Changes the sound of the intake tube (allows more air in from the resonance chamber).