1998 Buick Skylark Owner's Manual - Page 226

Fuel 0 Be sure you have sufficient knowledge, experience, the proper replacement parts and tools before you attempt any vehicle maintenance task. Be sure to use the proper nuts, bolts and other fasteners. "English" and "metric" fasteners can be easily confused.you use If the wrong fasteners, parts can later break You could be hurt. or fall off. Use regular unleaded gasoline rated at 87 octane or higher. At a minimum,it should meet specifications ASTM D4814 in United States and CGSB 3.5-M93 the in Canada. Improved gasoline specifications have been developed by the American Automobile Manufacturers Association (AAMA)for better vehicle performance and engine protection. Gasolines meeting the AAMA specification could provide improved driveability and emission control system protection compared to other gasolines. Be surethe posted octane is at least If the octaneis 87. less than 87, you may get a heavy knocking noise when you drive. If it's bad enough,it can damage your engine. Adding Equipment to the Outside of Your Vehicle Things you might add the outside of your vehicle can to affect the airflow aroundit. This may cause wind noise and affect windshield washer performance. Check with your dealer before adding equipment the outside of to your vehicle. If you're usingfuel rated at 87 octane or higher and you hear heavy knocking, your engine needs service. But little pinging noise when don't worryif you hear a you're accelerating or driving up a hill. That's normal, and you don't have to buy a higher octane to get rid fuel of pinging. It'sthe heavy, constant knock that means you have a problem. 6-3