Rummaging around on my engine today and found a hard plastic tube that
seemingly serves no purpose. Can't find it in the Bentley anywhere. It is
attached to the hose between the AFM and the Idle Stabilize. Goes forward
around the front top the engine then through a hole in the fire wall. It
isn't attached to anthing. Nothing for it to attach to. When the engine is
running it is definitely pulling a small vavuum which feeds in to that hose
the stabilizer is on. The way its hooked on it is supplying vacuum fed air
into the main air flow from the AFM, just down stream of the AFM before
going into te engine. What is this? What does it do. Should it be plugged
so it doesn't draw air, left unplugged so it does.

I'm lost!!!

Any suggestions as to what this is?

Thanks ,

John