The Myth:  Higher octane or “premium” gasoline will improve the performance of my car's engine.

The Evidence:  Octane rating is the measure of a gasoline's ability to resist knock or ping during combustion. The higher the octane rating, the greater the engine's resistance to knock or ping. The knocking or pinging in your engine occurs when the air/fuel mixture detonates prematurely.  Car manufacturers specify the minimum octane to be used with their automobiles. Virtually nothing is gained by using a higher octane or “premium” grade of fuel. If you already use the recommended octane fuel, you will not obtain more power from higher-octane fuels. There is little difference in energy content of regular versus premium gasoline. They both contain about 111,400 British Thermal Units of energy per gallon. Your drivability and fuel economy will remain the same. The higher-octane fuel costs more, so you are just wasting money.

The Verdict:  False