2009 Lexus LS 600h Owners Manual - Page 653

6-1. Specifications Fuel information You must only use unleaded gasoline in your vehicle. Premium unleaded gasoline with an octane rating of 91 (Research Octane Number 96) or higher required for optimum engine performance. If 91 octane cannot be obtained, you may use unleaded gasoline with an octane rating as low as 87 (Research Octane Number 91). Use of unleaded gasoline with an octane rating lower than 91 may result in engine knocking and significantly reduced performance. Persistent knocking can lead to engine damage and should be corrected by refueling with higher octane unleaded gasoline. At minimum, the gasoline you use should meet the specifications of ASTM D4814 in the U.S.A. and CGSB3.5-M93 in Canada. n Fuel tank opening for unleaded gasoline To help prevent incorrect fueling, your Lexus has a fuel tank opening that only accommodates the special nozzle on unleaded fuel pumps. n If your engine knocks l Consult your Lexus dealer. l You may occasionally notice light knocking for a short time while accelerating or driving uphill. This is normal and there is no need for concern. n Gasoline quality In very few cases, driveability problems may be caused by the brand of gasoline you are using. If driveability problems persist, try changing the brand of gasoline. If this does not correct the problem, consult your Lexus dealer. n Gasoline quality standards l Automotive manufacturers in the US, Europe and Japan have developed a specification for fuel quality called World-Wide Fuel Charter (WWFC) that is expected to be applied worldwide. l The WWFC consists of four categories that are based on required emission levels. In the US, category 4 has been adopted. l The WWFC improves air quality by lowering emissions in vehicle fleets, and customer satisfaction through better performance. 658