04 SS here. I'm having trouble understanding my EVAP system, I know, shocking. I've got a P0455, and before you say it, I've already replaced the gas cap, but the light is still on. When I unhook my vent valve and physically look at what I feel should be an actuated solenoid, I see nothing. I see an unloaded spring and regardless of cold start or hot start, that solenoid never actuates my valve to the closed position. Is it possible my solenoid is bad, which is constanly leaving my valve/canister open to atmosphere and making my fuel tank think it can't pull a vacuum because that solenoid won't ever shut and let it pull a vacuum through the charcoal canister?

Does the logic there seem, well, logical? Is this a common problem? Does anybody have a part number? Any help would be appreciated. I've checked just about every hose and connection I could get to and nothing was loose or disconnected.