240 DRIVING AND OPERATINGa posted octane rating of less than 87,as this may cause engine knock andwill lower fuel economy.If the vehicle has an LTG 2.0L L4Turbo engine, premium unleadedgasoline meeting ASTM specificationD4814 with a posted octane rating of93 is highly recommended for bestperformance and fuel economy.Unleaded gasoline with an octanerated as low as 87 can be used. Usingunleaded gasoline rated below93 octane, however, will lead toreduced acceleration and fueleconomy. If knocking occurs, use agasoline rated at 93 octane as soon aspossible, otherwise, the engine couldbe damaged. If heavy knocking isheard when using gasoline with a93 octane rating, the engine needsservice.If the vehicle has an LF3 3.6L V6 TwinTurbo or the LT4 V8 engine, usepremium unleaded gasoline meetingASTM specification D4814 with aposted octane rating of 93.If unavailable, unleaded gasoline witha posted octane rating of 91 may beused, but with reduced performanceand fuel economy. If the octane is lessthan 91, the engine could be damagedand the repairs would not be coveredby the vehicle warranty. If heavyknocking is heard when using gasolinerated at 93 octane, the engine needsservice.Prohibited FuelsCautionDo not use fuels with any of thefollowing conditions; doing so maydamage the vehicle and void itswarranty:. For vehicles which are notFlexFuel, fuel labeled greaterthan 15% ethanol by volume,such as mid-level ethanolblends (16 – 50% ethanol),E85, or FlexFuel.. Fuel with any amount ofmethanol, methylal, andaniline. These fuels cancorrode metal fuel systemparts or damage plastic andrubber parts.(Continued)Caution (Continued). Fuel containing metals suchas methylcyclopentadienylmanganese tricarbonyl(MMT), which can damagethe emissions control systemand spark plugs.. Fuel with a posted octanerating of less than therecommended fuel. Using thisfuel will lower fuel economyand performance, and maydecrease the life of theemissions catalyst.California FuelRequirementsIf the vehicle is certified to meetCalifornia Emissions Standards, it isdesigned to operate on fuels that meetCalifornia specifications. See theunderhood emission control label.If this fuel is not available in statesadopting California EmissionsStandards, the vehicle will operatesatisfactorily on fuels meeting federalspecifications, but emission control
