2005 Dodge Viper Owner's Manual - Page 142

142 STARTING AND OPERATING FUEL REQUIREMENTS Your vehicle is designed to meet all emission regulations and provide excellent fuel economy when using high quality premium unleaded gasoline having an octane rating of 91 or higher. Spark Knock 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) to 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. Reformulated Gasoline Many areas of the country require the use of cleaner burning fuel referred to as Reformulated Gasoline. Reformulated gasolines contain oxygenates, and are specially blended to reduce vehicle emissions and improve air quality. The manufacturer strongly supports the use of reformulated gasolines. Properly blended reformulated gasolines will provide excellent performance and durability of engine and fuel system components.