1996 Ford Aerostar Owner's Manual - Page 255

Fuel quality If you are experiencing starting, rough idle or hesitation problems when the engine is cold, it may be caused by fuel with low volatility. Try a different brand of fuel. If the condition persists, see your dealer or a qualified service technician. Using a high-quality fuel makes your vehicle more responsive and maintains its good fuel economy and emissions by: u minimizing deposits in fuel injectors, combustion chambers and on intake valves. u assuring quick starting and smooth warm-up. u protecting the fuel system from vapor lock in very hot weather, which causes the engine to hesitate or stall and makes restarts difficult. u protecting your fuel system from rusting. u preventing the fuel lines from freezing. u preventing the fuel system from "gumming It should not be necessary to add any aftermarket products to your fuel tank if you continue to use a high-quality fuel. Gasolines for clean air up" when your vehicle is not used for long periods of time. Fuels in certain areas of the country are required to contain oxygenates to improve air quality. Common oxygenates are ethanol or grain alcohol (blended at no more than 10%), methanol or wood alcohol (blended at no more than 5% with cosolvents and additives), and MTBE or methyl tertiary butyl ether (blended at no more than 15%). 277