1998 Cadillac DeVille Owner's Manual - Page 290

Fuel You can beinjured and your vehicle could be on damaged if you try to do service work a vehicle without knowing enough about it. 0 Be sure you have suffkient knowledge, experience, the proper replacement parts and tools before you attempt any vehicle maintenance task. Be sure to use theproper nuts, boltsand other fasteners. "English"and "metric" I you use f fasteners can be easily confused. the wrong fasteners, parts can later break or fall off. You could behurt. Use premiumudeaded gasoline rated at octane or 91 higher for best performance. You may use middle grade or regular unleaded gasolines, but your vehicle may not accelerate as well. At a minimum, gasoline you use should meet the specifications ASTM D4814in the United States and CGSB 3.5-M93 in Canada. Improved gasoline specifications have been developed by the American (AAMA) for Automobile Manufacturers Association better vehicle performance and engine protection. Gasolines meetingthe AAMA specification could provide improved driveability and emission control system protection compared other gasolines. to Be surethe posted octane for premium is at 1,east91 (at least 89for middle grade and 87 regular). If the for octane is less than 87, you may get a heavy knocking If noise when you drive. it's bqd enough, it can damage your engine. If you're usingfuel rated atthe recommended octane or higher and you hear heavy knocking, your engine needs service. But don't worry if you hear a pinging little hill. noise when you're accelerating or driving up a That's normal, and you don't have to buy a higher Adding Equipment to the Outside of Your Vehicle Things you might add the outside of your vehicle can to affect the airflow around it. This may cause wind noise and affect windshield washer performance. Check with your dealer before adding equipment the outside of to your vehicle. 6-3