If the vehicle has the 6.2L supercharged V8 engine(VIN Code P), use premium unleaded gasoline witha posted octane rating of 91 or higher. For bestperformance, use premium unleaded gasoline with aposted octane rating of 93. In an emergency, you can useregular unleaded gasoline with an octane rating of 87 orhigher. If 87 octane fuel is used, do not perform anyaggressive driving maneuvers such as wide open throttleapplications. You might also hear audible spark knockduring acceleration. Refill the tank with premium fuel assoon as possible to avoid damaging the engine. If you areusing gasoline rated at 91 octane or higher and you hearheavy knocking, the engine needs service.Gasoline SpecificationsAt a minimum, gasoline should meet ASTM specificationD 4814 in the United States or CAN/CGSB-3.5 or3.511 in Canada. Some gasolines contain anoctane-enhancing additive called methylcyclopentadienylmanganese tricarbonyl (MMT). We recommendagainst the use of gasolines containing MMT. SeeAdditives on page 5-7 for additional information.California FuelIf the vehicle is certified to meet California EmissionsStandards, it is designed to operate on fuels thatmeet California specifications. See the underhoodemission control label. If this fuel is not availablein states adopting California emissions standards, thevehicle will operate satisfactorily on fuels meeting federalspecifications, but emission control system performancemight be affected. The malfunction indicator lampcould turn on and the vehicle might fail a smog-checktest. See Malfunction Indicator Lamp on page 3-42.If this occurs, return to your authorized dealer/retailer fordiagnosis. If it is determined that the condition iscaused by the type of fuel used, repairs might not becovered by the vehicle warranty.AdditivesTo provide cleaner air, all gasolines in the United Statesare now required to contain additives that help preventengine and fuel system deposits from forming, allowingthe emission control system to work properly. In mostcases, you should not have to add anything to the fuel.However, some gasolines contain only the minimumamount of additive required to meet U.S. EnvironmentalProtection Agency regulations. To help keep fuel injectorsand intake valves clean, or if the vehicle experiencesproblems due to dirty injectors or valves, look for gasolinethat is advertised as TOP TIER Detergent Gasoline.5-7
