Its your evaporative canister purge vacuum diaphragm. Its number 15 in the following picture.
That hose coming off of it - from what my system shows - is just a vent hose... kinda like a differential vent line. So, it really doesnt hook to anything. If I am incorrect in this, somebody point it out to me please. [img]images/graemlins/40BEER.gif[/img]