1993 Pontiac Sunbird Owner's Manual - Page 150

If you're using fuel rated 87 octane or at higher and you still hear heavy knocking, your engine needs service. if But don't worry you hear a little pinging noise when you're accelerating or driving upa hill. That's normal,and you don't haveto buy a higher octane fuel to get rid of pinging. It's the heavy, constant knockthat means you have a problem. What about gasoline with blending materials that contain oxygen (oxygenates), such as MTBE or alcohol? MTBE is "methyl tertiary-butyl ether." Fuel that is no morethan 15%MTBE is fine for your vehide. Ethanol is ethyl or grain alcohol. Properly-blended fuelthat is no more than 10% ethanol is fine for your vehicle. Methanol is methyl or wood alcohol. NOTICE: Fuel that is morethan 5% methanol is bad for your vehicle. Don't useit. It can corrode metal parts in your fuel systemand also damage plasticand rubber parts. That damage wouldn't be covered under yourwarranty. And evenat 5% or less, there must be "cosolvents" and corrosion preventers in this fuel to help avoid these problems. Gasolines for Cleaner Air Your use of gasoline with deposit control additives will help prevent deposits from forming your engine in and fuel system.That helps keep your engine in tune and your emission control system working properly. It's good for your vehicle, you'll be and doing yourpart for cleanerair. Many gasolinesare now blendedwith oxygenates. General Motors recommends that you use gasolines with these blending materials,such as MTBE and ethanol. By doing so, you can help cleanthe air,especially in those parts of the country that have highcarbonmonoxidelevels. In addition, some gasolinesuppliers are now producing reformulated gasolines. These gasolines are specially designed to reduce vehicle emissions.General Motors recommendsthat you use reformulated gasoline. By doing go, you can help cleanthe air, especially in those parts of the country that have high ozone levels. You should ask your service station operators if their gasolines contain deposit control additives and oxygenates, andif they have beep reformulated to reduce vehicle ; emissions. ., ,* i :* $1 14S.l.