GM Service Manual Online
For 1990-2009 cars only

Use regular unleaded gasoline rate at 87 octane or higher. It is recommended that the gasoline meet specifications which have been developed by the American Automobile Manufacturers Association (AAMA) and endorsed by the Canadian Motor Vehicle Manufacturers Association for better vehicle performance and engine protection. Gasolines meeting the AAMA specification could provide improved driveability and emission control system performance compared to other gasolines. For more information, write to: American Automobile Manufacturers Association, 7430 Second Ave, Suite 300, Detroit, MI 48202.

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. The use of gasoline that is less than 87 octane can damage your engine.

If you are using fuel rated at 87 octane or higher and you hear heavy knocking, the engine needs service. However, it is normal to hear a little pinging noise when you are accelerating or driving up a hill. It is the sound of constant knock that means the engine has a problem.