Lubricates the entire fuel system: fuel pumps, fuel injectors or carburetors and the top portion of the cylinders Improves fuel mileage by reducing internal friction in the engine Note for diesel fuel users: this diesel fuel additive does not comply with federal low sulfur content requirements for use in model 2007 and newer diesel motor vehicles Extends life of vital components by providing them with lubrication that fuel alone does not provide Spark plug life is also extended by using Marvel in your fuel