2008 Jeep Wrangler Owner's Manual - Page 338

STARTING AND OPERATING 337 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. 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. MMT In Gasoline MMT is a manganese containing metallic additive that is blended into some gasoline to increase the octane number. Gasoline blended with MMT offers no performance advantage beyond gasoline of the same octane number without MMT. Gasoline blended with MMT has shown to reduce sparkplug life and reduce emission system performance in some vehicles. The manufacturer recommends that gasoline without MMT be used in your vehicle. The MMT content of gasoline may not be indicated on the gasoline pump, therefore, you should ask your gasoline retailer if the gasoline contains MMT. 5 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.