Does high-octane gasoline provide better gas...

High-octane gas will not give you better gas mileage. It may, however, quiet your car’s engine by burning cleaner than regular gasoline. According to the American Automobile Association, only about 5 percent of cars sold in the United States really need to use premium gas. If you’ve been using high-octane gas and want to save money, buy a tankful of regular and listen to the engine as you drive. If you hear your engine “knocking,” go back to premium. If there is no knock, you’ve found a money-saving trick.