2012 Jeep Grand Cherokee Owner Manual SRT - Page 473

STARTING AND OPERATING 471 FUEL REQUIREMENTS 6.4L Engine The 6.4L engine is designed to meet all emissions regulations and provide excellent fuel economy and performance when using high-quality premium unleaded gasoline with an octane rating of 91 or Reformulated Gasoline higher. Many areas of the country require the use of cleaner Light spark knock at low engine speeds is not harmful to burning gasoline referred to as "reformulated gasoline." your engine. However, continued heavy spark knock at Reformulated gasolines contain oxygenates and are spehigh speeds can cause damage and immediate service is cifically blended to reduce vehicle emissions and imrequired. Poor quality gasoline can cause problems such prove air quality. as hard starting, stalling, and hesitations. If you experience these symptoms, try another brand of gasoline The manufacturer supports the use of reformulated gasolines. Properly blended reformulated gasolines will probefore considering service for the vehicle. vide excellent performance and durability of engine and fuel system components. Over 40 auto manufacturers worldwide have issued and endorsed consistent gasoline specifications (the Worldwide Fuel Charter, WWFC) which define fuel properties necessary to deliver enhanced emissions, performance, and durability for your vehicle. The manufacturer recommends the use of gasolines that meet the WWFC specifications if they are available. 5