Ian -
I have the '06 Chevy version of your truck (crew cab Z71) - but I can't seem to locate the canister. I've looked at the pics that have been posted here - crawled under the truck yesterday (it's cold in Indy right now) but no luck. Where was it located on your truck? I think if I can physically "see" it, life will be a bit simpler from there. Hopefully it isn't mounted somewhere on top of the tank?
Thanks in advance.