1997 Chevrolet Cavalier Owner's Manual - Page 246

Be surethe posted octane is at least 87. If the octane is less than 87, you may geta 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 or higher and you hear heavy knocking, yourengine needs service. But don't worry if you heara little pinging noise when you're accelerating or driving up a hill. That's normal, and you don't have to buy a higher octane fuel to get rid of pinging. It's the heavy,constant knock that means you have a problem. your instrument panel may turn on and/or your vehicle may fail a smog-check test. If this occurs, return to your authorized Chevrolet dealer for diagnosis to determine the cause of failure. In the eventit is determined that the cause of the condition is the type fuels used, repairs of may not be covered by your warranty. Some gasolines that are not reformulated low for emissions containan octane-enhancing additive called methylcyclopentadienyl manganese tricarbonyl (MMT); ask yourservice station operator whether or not his fuel contains MMT, General Motors does not recommend the use of such gasolines. If fuels containing MMT are used, spark pluglife may be reduced and your emission control system performance may be affected. The malfunction indicator lamp on your instrument panel may turn on. If this occurs, return to your authorized Chevrolet dealer for service. If your vehicleis certified to meet California Emission Standards (indicated on the underhood tune-up label), it is designed tooperate on fuels that meet California specifications. If such fuels are not available in states adopting California emissions standards, your vehicle will operate satisfactorily on fuels meeting federal specifications, but emissioncontrol system performance may be affected.The malfunction indicator lamp on