1997 Cadillac DeVille Owner's Manual - Page 286

Adding Equipment to the Outside of Your Vehicle Things you might add to outside of your vehiclecan the affect the airflow around it. This may cause wind noise and affectwindshield washer performance. Check with your Cadillac dealer before adding equipment to the outside of your vehicle. Fuel Use premium unleaded gasoline ratedat 91 octane or higher. Ata minimum, it should meet specifications ASTM D4814in the United States and CGSB 3.5-M93 in Canada. Improved gasoline specificationshave been developed by the American Automobile Manufacturers Association (AAMA) for better vehicleperformance and engine protection. Gasolines meeting the AAMA specification couldprovide improved driveability and emission control system protection compared to other gasolines. Be sure the posted octane for premium is at least 91. If the octane is less than91, you may get a heavy knocking noise when you drive. (In an emergency, you may be able to usea lower octane -- as low as 87 -- if heavy knocking does not occur.) If you're using 91 or higher octane unleaded gasoline and you hear heavy knocking, your engine needs service. If your vehicle is certified to meet California Emission Standards (indicated on the underhood tune-up label), it is designed to operateon fuels that meet California specifications. If such fuels are not available in states adopting California emissions standards, your vehicle will operate satisfactorilyon fuels meeting federal specifications, butemission control system performance may be affected. The malfunction indicatorlamp on your instrument panel may turn on and/or your vehicle may fail a smog-check test. If this occurs, return to your authorized Cadillac dealer diagnosis todetermine the for cause of failure. In the event it is determined that the cause of the conditionis the type of fuels used, repairs may not becovered by your warranty. Some gasolines that are not reformulated low for emissions contain an octane-enhancing additive called methylcyclopentadienylmanganese tricarbonyl (MMT); ask your service station operator whether or not this fue contains MMT. General Motors does not recommend the use of such gasolines.If fuels containing MMT are used,spark plug life may be reduced and your emission control system performance may be affected. The malfunction indicator lamp on your instrument panel may turnon. If this occurs, return to your authorized Cadillac dealer service. for 6-3