Sorry, I had to run for work, and didn't have time to give you a very good answer on the vapor canister. I think the vapor canister is tied into the emissions system, and serves to remove something or other from the fuel vapors before they go back to the tank, but exactly what it does escapes me.

All my cars are pre-emissions, so I haven't dealt with one of these in years. Someone else will know though, I'm sure.

Don