Adding Equipment to the Outside ofYour VehicleThings you might add to the outside of yourvehicle can affect the airflow around it. This maycause wind noise and affect windshield washerperformance. Check with your dealer beforeadding equipment to the outside of your vehicle.FuelUse of the recommended fuel is an important partof the proper maintenance of your vehicle. Tohelp keep your engine clean and maintain optimumvehicle performance, GM recommends the useof gasoline advertised as TOP TIER DetergentGasoline.Gasoline OctaneUse premium unleaded gasoline with a postedoctane rating of 91 or higher. You may alsouse regular unleaded gasoline rated at 87 octaneor higher, but your vehicle’s acceleration maybe slightly reduced, and you may notice a slightaudible knocking noise, commonly referred toas spark knock. If the octane is less than 87, youmay notice a heavy knocking noise when youdrive. If this occurs, use a gasoline rated at87 octane or higher as soon as possible.Otherwise, you might damage your engine. If youare using gasoline rated at 87 octane or higherand you hear heavy knocking, your engine needsservice.Gasoline SpecificationsAt a minimum, gasoline should meet ASTMspecification D 4814 in the United States orCAN/CGSB-3.5 in Canada. Some gasolines maycontain an octane-enhancing additive calledmethylcyclopentadienyl manganese tricarbonyl(MMT). General Motors recommends against theuse of gasolines containing MMT. See Additiveson page 400 for additional information.399InformationProvidedby:
