2006 Lincoln Navigator Owner Guide 2nd Printing - Page 366

Maintenance and Specifications Octane recommendations Your vehicle is designed to use "Premium" unleaded gasoline with an (R+M)/2 octane rating of 91 or higher for optimum performance. (R+M)/2 METHOD The use of gasolines with lower octane ratings may degrade performance. The use of gasolines labeled as "Premium" in high altitude areas that are sold with octane ratings of less than 91 is 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. 91 Fuel quality If you are experiencing starting, rough idle or hesitation driveability problems during a cold start, try a different brand of gasoline. If the problems persist, see your authorized dealer. 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. Aftermarket products 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. Running out of fuel Avoid running out of fuel because this situation may have an adverse effect on powertrain components. If you have run out of fuel: • You may need to cycle the ignition from off to on several times after refueling, to allow the fuel system to pump the fuel from the tank to the engine. 366 2006 Navigator (nav) Owners Guide (post-2002-fmt) USA (fus)