Is there any benefit to keeping the Evaporative Canister connected? Do you get better MPG without it connected?
No not really and if you did your whole pollution system would have to be in new or near new working condition
The system neither robs power or creates power. It simply routs the fuel vapors from the fuel tank back into the carb to be burned. If you disconnect it, the vapors will be coming out the metal line that is left. Not a good thing to do although I have never heard of any problems by removing it.