In my nearly four decades of car ownership, I have driven a staggering variety of vehicles, from vintage Jeep CJ5s and CJ7s and International Scouts to turbocharged late-model Volkswagens and BMWs.

Sometimes, drivers don't even realize they own a flex-fuel vehicle. If your car has a small label near the yellow gas cap that says E85 or Flex Fuel, then you're in luck. Obviously, these cars look ...

The price difference during a fill-up between regular and premium gas can be eye-opening. As of this writing, the U.S. Energy Information Administration reports that the average price for a gallon of ...