Which hose is this?

[KozmoNaut]

I was rummaging around under the bonnet, trying to identify the cause of the rattly/resonance-y sound my 406 (2.2L EW12J4) makes at ~1900 RPM, when I noticed this hose looking a bit worse for wear.

Can anyone identify it? It seems to be going to the air filter box, but I'm not 100% sure. It's on the right side of the engine, when looking at it from the front.


(Click for embiggening)

Since there is no hose clamp on it, I assume it isn't vital to performance or economy or anything of that nature. But I would still love to know what it is :-)

[406Break]

Looks like it could be a part of the Exhaust gas recycling circuit.
Depending on engine serial no. (small differences)

[KozmoNaut]

It looks like hose #8 on those diagrams. I've patched it up with some tape.