1995 Pontiac Trans Sport Owner's Manual - Page 272

Be sure the posted octane is at least 87. If the octane is less than 87, you may get a heavy knocking noise when you drive. If it's bad enough, it can damage your engine. If you're using fuel rated at 87 octane orhigher and you still hear heavy knocking, your engine needs service. But don't worry if you hear a little pinging noise when you're accelerating or driving up hill. That's normal, a and you don't have to buy a higher octane fuel to rid get of pinging. It's the heavy, constant knock that means you have a problem. I NOTICE: Fuel that is more than 5% methanol is bad for your vehicle. Don't use it. It can corrode metal parts in your fuel system also damage plastic and and rubberparts. That damage wouldn't be covered under your warranty. And evenat 5 % or less, there must be "cosolvents"and corrosion preventers in this fuel to help avoid these 1 problems. 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 more t h a ~ 15% MTBE is fine for your vehicle. Ethanol is ethyl or grain alcohol. Properly-blended fuel that is no more than 10%ethanol is fine for your vehicle. Methanol is methyl or wood alcohol. 6-3