2010 Jeep Wrangler Owner's Manual - Page 413

412 STARTING AND OPERATING Over 40 auto manufacturer's worldwide have issued and endorsed consistent gasoline specifications (the Worldwide Fuel Charter, WWFC) to define fuel properties necessary to deliver enhanced emissions, performance, and durability for your vehicle. The manufacturer recommends the use of gasoline that meets the WWFC specifications if they are available. Reformulated Gasoline Many areas of the country require the use of cleaner burning gasoline referred to as "Reformulated Gasoline." Reformulated gasoline contains oxygenates, and are specifically blended to reduce vehicle emissions and improve air quality. The manufacturer supports the use of reformulated gasoline. Properly blended reformulated gasoline will provide excellent performance and durability for the engine and fuel system components. Gasoline/Oxygenate Blends Some fuel suppliers blend unleaded gasoline with oxygenates such as 10% ethanol, MTBE, and ETBE. Oxygenates are required in some areas of the country during the winter months to reduce carbon monoxide emissions. Fuels blended with these oxygenates may be used in your vehicle. CAUTION! Do not use gasolines containing Methanol. Use of these blends may result in starting and drivability problems and may damage critical fuel system components. Problems that result from using methanol/gasoline blends are not the responsibility of the manufacturer. While MTBE is an oxygenate made from Methanol, it does not have the negative effects of Methanol.