Vehicles that are listed as Flex Fuel will allow you to burn E85(and other fuels), which is 85% ethanol(corn) to 15% gasoline. In NY E85 availability is very limited. Our gasoline now is 15% ethanol and 85% gasoline. Emissions are reduced with ethanol, hence the reason its added, but efficiency is lost as you will burn more ethanol per mile then (petroleum based)gas. And I think its a lot more. Here’s the wiki for Flex Fuel:
https://en.wikipedia.org/wiki/Flexible-fuel_vehicle
Ron
