2005 Chrysler 300 Owner's Manual - Page 252

252 STARTING AND OPERATING MMT In Gasoline MMT is a manganese containing metallic additive that is blended into some gasoline to increase the octane number. Gasolines blended with MMT offer no performance advantage beyond gasolines of the same octane number without MMT. Gasolines blended with MMT have shown to reduce spark plug life and reduce emission system performance in some vehicles. The manufacturer recommends using gasolines without MMT. Since the MMT content of gasoline may not be indicated on the pump, you should ask your gasoline retailer whether or not his/her gasoline contains MMT. It is even more important to look for gasolines without MMT in Canada, because MMT can be used at levels higher than those allowed in the United States. MMT is prohibited in Federal and California reformulated gasolines. Sulfur In Gasoline Your vehicle may have been designed to meet California low emission standards when using cleaner burning California reformulated gasoline with low sulfur. This vehicle may be sold nationwide. Your vehicle will operate satisfactorily on fuels meeting Federal specification, but emission control system performance may be adversely affected. Gasoline sold outside of California is permitted to have higher sulfur levels which may affect the performance of the vehicle's catalytic converter. This may cause the Malfunction Indicator Light to illuminate. The manufacturer recommends that you try a different brand of unleaded gasoline having lower sulfur to determine if the problem is fuel related prior to returning your vehicle to an authorized dealer for service. CAUTION! If the Malfunction Indicator light is flashing, immediate service is required. Refer to the paragraph on the Onboard Diagnostics System in section 7 of this manual.