FORD 1998 Taurus - Manual (Page 158)

Choosing the right fuel
Use only UNLEADED FUEL. The use of leaded fuel
is prohibited by law and could damage your vehicle.
Your vehicle was not designed to use fuel or fuel
additives with metallic compounds, including
manganese-based compounds containing (MMT).
Vehicles certified to meet 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 for which
your vehicle was not designed may not be covered
by your warranty.
Octane recommendations
3.0L V6 Vulcan and Duratec engines
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 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
(R+M)/2 METHOD
Maintenance and care
158