Ford Mystique Owner's Manual page 207

Choosing the Right Fuel
Use only UNLEADED FUEL. Using leaded fuel is prohibited by
federal law and could damage your vehicle. The damage may
not be covered by your warranty.
Your vehicle was not designed to use fuel containing
manganese-based additives such as MMT. Additionally, vehicles
certified to California emission standards (indicated on the
underhood Vehicle Emissions Control Information label) are
designed to operate on California reformulated gasolines. If
California reformulated gasoline is not available when you
refuel, your vehicle can be operated on non-California fuels.
However, even though your engine will perform adequately on
other gasolines, the performance of the emission control devices
and systems may be adversely affected. Repair of damage
caused by using a fuel that your vehicle was not designed for
may not be covered by your warranty.
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