2011 Ford Mustang Owner Guide 3rd Printing - Page 289

Maintenance and Specifications WARNING: The fuel system may be under pressure. If you hear a hissing sound near the fuel filler door (Easy Fuel™ "no cap" fuel system), do not refuel until the sound stops. Otherwise, fuel may spray out, which could cause serious 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. 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. 87 289 2011 05+ Mustang (197) Owners Guide, 3rd Printing USA (fus)