2007 Dodge Charger Owner's Manual - Page 250

250 STARTING AND OPERATING FUEL REQUIREMENTS 2.7L Engine Your vehicle is designed to meet all emissions regulations and provide satisfactory fuel economy and performance when using high quality unleaded gasoline having an octane of 87. 3.5L and 5.7L Engines The 3.5L and 5.7L engines are designed to meet all emissions regulations and provide satisfactory fuel economy and performance when using high-quality unleaded gasoline with an octane rating of 87 to 89. The manufacturer recommends the use of 89-octane for optimum performance. The routine use of premium gasoline is not recommended. The use of premium gasoline will provide no benefit over high quality regular gasoline or mid-grade gasoline and in some circumstances may result in poorer performance. Light spark knock at low engine speeds is not harmful to your engine. However, continued heavy spark knock at high speeds can cause damage and immediate service is required. Poor quality gasoline can cause problems such as hard starting, stalling, and hesitations. If you experience these symptoms, try another brand of "regular" gasoline before considering service for the vehicle. Over 40 automobile manufacturers around the world have issued and endorsed consistent gasoline specifications (the World Wide Fuel Charter, WWFC) which define fuel properties necessary to deliver enhanced emissions, engine performance, and durability for your vehicle. The manufacturer recommends the use of gasolines that meet the WWFC specifications if they are available.