2000 Subaru Outback Owner's Manual - Page 239

Fuel CAUTION Use of a fuel which is low in quality or use of an inappropriate fuel additive may cause engine damage. J Fuel requirements B Fuel Octane Rating Your engine is designed to use only unleaded gasoline with an octane rating of 87 AKI or higher. This octane rating is the average of the Research Octane and Motor Octane numbers and is commonly referred to as the Anti Knock Index (AKI). Using a gasoline with a lower octane rating can cause persistent and heavy knocking, which can damage the engine. Do not be concerned if your vehicle sometimes knocks lightly when you drive up a hill or when you accelerate. See your dealer or a qualified service technician if you use a gasoline with the specified octane rating and your vehicle knocks heavily or persistently. B Unleaded gasoline The neck of the fuel filler pipe is designed to accept only an unleaded gasoline filler nozzle. Under no circumstances should leaded gasoline be used because it will damage the emission control system and may impair driveability and fuel economy. B Gasoline for California-certified LEV If your vehicle is a California-certified Low Emission Vehicle (LEV) as indicated on the underhood tune-up label, it is designed to optimize engine and emission control system performance with gasoline that meets California low sulfer specifications. Your vehicle will operate on gasoline meeting Federal specifications. 7-2