1999 Mercury Grand Marquis Owner Guide 1st Printing - Page 160
1999 Mercury Grand Marquis Manual
Page 160 highlights
Maintenance and care Do not use gasolines containing methanol. It can damage critical fuel systems components. Vehicles certified to meet California emission standards (indicated on the underhood Vehicle Emissions Control Information label) are designed to operate on California cleaner-burning, low-sulfur gasolines. If you have a California-certified vehicle and California cleaner-burning gasoline is not available when you refuel, your engine should perform adequately. However, the performance of the emission control devices and systems may be adversely affected. In New York and Massachusetts, which have adopted California's emission standards without requiring the sale of California cleaner-burning gasoline, repairs to correct the effects of using non-California fuel may not be covered by the emissions warranty. Your vehicle was not designed to use fuel or fuel additives with metallic compounds, including manganese-based compounds containing (MMT). Repairs to correct the effects of using a fuel for which your vehicle was not designed may not be covered by your warranty. Octane recommendations Your vehicle is designed to use "Regular" unleaded gasoline with an (R+M)/2 octane rating of 87. We do not recommend the use of gasolines (R+M)/2 METHOD labeled as "Regular" that are sold with octane ratings of 86 or lower in high altitude areas. Do not be concerned if your engine sometimes knocks lightly. However, if it knocks heavily under most driving conditions while you are using fuel with the recommended octane rating, see your dealer or a qualified service technician to prevent any engine damage. 87 Fuel quality If you are experiencing starting, rough idle or hesitation driveability problems during a cold start, try a different brand of "Regular" unleaded gasoline. "Premium" unleaded gasoline is not recommended (particularly in the United States) because it may cause these problems to become more pronounced. If the problems persist, see your dealer or a qualified service technician. It should not be necessary to add any aftermarket products to your fuel tank if you continue to use a high-quality fuel. 160