2010 Jeep Liberty Owner's Manual - Page 385

384 STARTING AND OPERATING MMT can be used at levels higher than those allowed in the United States. MMT is prohibited in Federal and California reformulated gasoline. Materials Added To Fuel All gasoline sold in the United States is required to contain effective detergent additives. Use of additional detergents or other additives is not needed under normal conditions and they would result in additional cost. Therefore, you should not have to add anything to the fuel. Fuel System Cautions CAUTION! (Continued) • The use of leaded gas is prohibited by Federal law. Using leaded gasoline can impair engine performance, and damage the emission control system. • An out-of-tune engine, or certain fuel or ignition malfunctions, can cause the catalytic converter to overheat. If you notice a pungent burning odor or some light smoke, your engine may be out of tune or malfunctioning and may require immediate service. Contact your authorized dealer for service assistance. • The use of fuel additives, which are now being sold as octane enhancers, is not recommended. Most of these products contain high concentrations of methanol. Fuel system damage or vehicle performance problems resulting from the use of such fuels or additives is not the responsibility of the manufacturer. CAUTION! Use the following guidelines to maintain your vehicle's performance: (Continued)