2009 Lincoln MKZ Owner's Manual - Page 267

Maintenance and Specifications WARNING: The fuel system may be under pressure. If the fuel filler cap is venting vapor or if you hear a hissing sound, wait until it stops before completely removing the fuel filler cap. Otherwise, fuel may spray out and injure you or others. WARNING: If you do not use the proper fuel filler cap, excessive vacuum in the fuel tank may damage the fuel system or cause the fuel cap to disengage in a collision, which may result in personal injury. Choosing the right fuel Use only UNLEADED fuel or UNLEADED fuel blended with a maximum of 10% ethanol. Do not use fuel ethanol (E85), diesel, methanol, leaded fuel or any other fuel. The use of leaded fuel is prohibited by law and could damage your vehicle. Your vehicle was not designed to use fuel or fuel additives with metallic compounds, including manganese-based additives. Note: Use of any fuel other than those recommended may cause powertrain damage, a loss of vehicle performance, and repairs may not be covered under warranty. Octane recommendations Your vehicle is designed to use "Regular" unleaded gasoline with a pump (R+M)/2 octane rating of 87. We do not recommend the use of (R+M)/2 METHOD gasolines labeled as "Regular" in high altitude areas that are sold with octane ratings less than 87. 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. "Premium" unleaded gasoline is not recommended for vehicles designed to use "Regular" unleaded gasoline because it may cause these problems to become more pronounced. If the problems persist, see your authorized dealer. 267 2009 MKZ (378) Owners Guide, 2nd Printing USA (fus)