I have been told the vent valve on the evap canister is bad and the whole thing needs to be replaced. Could this truly be the case? If so, is it something a backyard mechanic can do, or does it need to be changed by a real mechanic? Or, can the valve be changed without replacing the entire canister?

Thanx

 

I would check first with your local dealer. There is a kit to relocate the vent valve to fix this issue and the one on my truck (2005) was replaced for free.