Here in Ohio there has been issues with unregulated unleaded fuel going to the pumps. This has been causing small engine machinery to cause issues in loosing the power they originally have had. All the local lawn mower and snowblower repair shops in my area have been getting tons of machines in with the same issues in the engines getting gummed up. So they are now telling people to stop using unleaded gas and use the mid grade stuff to resolve issues. So this is also showing issues in my truck as well. My dad just put in a full take of mid grade with no other changes and with no other part replacement and his fuel economy is already doing better. Not only is the mpg better but he had a bit of a rough idle and now it is no longer an issue.