2010 Ford F350 Super Duty Super Cab Owner Guide 2nd Printing - Page 375

Maintenance and Specifications Octane recommendations Your vehicle is designed to use "Regular" unleaded gasoline with a pump (R+M)/2 octane rating of 87. Some stations offer fuels posted as (R+M)/2 METHOD "Regular" with an octane rating below 87, particularly in high altitude areas. Fuels with octane levels below 87 are not recommended. Do not be concerned if your engine sometimes knocks lightly. However, if it knocks heavily under most driving conditions while you are using fuel with the recommended octane rating, see your authorized dealer to prevent any engine damage. 87 Fuel quality If you are experiencing starting, rough idle or hesitation driveability problems, try a different brand of unleaded gasoline. If the problems persist, see your authorized dealer. Do not add aftermarket fuel additive products to your fuel tank. It should not be necessary to add any aftermarket products to your fuel tank if you continue to use high quality fuel of the recommended octane rating. These products have not been approved for your engine and could cause damage to the fuel system. Repairs to correct the effects of using an aftermarket product in your fuel may not be covered by your warranty. Many of the world's automakers approved the World-Wide Fuel Charter that recommends gasoline specifications to provide improved performance and emission control system protection for your vehicle. Gasolines that meet the World-Wide Fuel Charter should be used when available. Ask your fuel supplier about gasolines that meet the World-Wide Fuel Charter. Cleaner air Ford endorses the use of reformulated "cleaner-burning" gasolines to improve air quality, per the recommendations in the Choosing the right fuel section. Running out of fuel Avoid running out of fuel because this situation may have an adverse effect on powertrain components. 375 2010 F-250/350/450/550 (f23) Owners Guide, 2nd Printing USA (fus)