DRIVING AND OPERATING 259Recommended Fuel (4.2LTwin Turbo V8 Engine)Use premium unleaded gasolinemeeting ASTM specification D4814with a posted octane rating of 93 —(R+M)/2. If unavailable, unleadedgasoline with a posted octane ratingof 91 may be used, but with reducedperformance and fuel economy. If theoctane is less than 91, the enginecould be damaged and the repairswould not be covered by the vehiclewarranty. If heavy knocking is heardwhen using gasoline rated at93 octane, the engine needs service.Do not use any fuel labeled E85 orFlexFuel. Do not use gasoline withethanol levels greater than 15% byvolume.Prohibited FuelsCautionDo not use fuels with any of thefollowing conditions; doing so maydamage the vehicle and void itswarranty:. For vehicles that 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, ferrocene,and aniline. These fuels cancorrode metal fuel systemparts or damage plastic andrubber parts.. Fuel containing metals suchas methylcyclopentadienylmanganese tricarbonyl(MMT), which can damagethe emissions control systemand spark plugs.(Continued)Caution (Continued). Fuel with a posted octanerating of less than therecommended fuel. Using thisfuel will lower fuel economyand performance, and maydecrease the life of theemissions catalyst.Fuels in Foreign CountriesThe U.S., Canada, and Mexico postfuel octane ratings in anti-knock index(AKI). For fuel not to use in a foreigncountry, see Prohibited Fuels 0 259.Fuel AdditivesTOP TIER Detergent Gasoline is highlyrecommended for use with yourvehicle. If your country does not haveTOP TIER Detergent Gasoline, addACDelco Fuel System Treatment Plus−Gasoline to the vehicle’s gasoline fueltank at every oil change or 15 000 km(9,000 mi), whichever occurs first. TOPTIER Detergent Gasoline and ACDelcoFuel System Treatment Plus−Gasoline
