Lincoln 2010 MKZ - Manual (Page 287)

WARNING: The fuel system may be under pressure. If you hear
a hissing sound near the fuel filler door (Easy Fuel™ “no cap”
fuel system), do not refuel until the sound stops. Otherwise, fuel may
spray out, which could cause serious personal injury.
Choosing the right fuel
Use only UNLEADED fuel or UNLEADED fuel blended with a maximum
of 10% ethanol. Do not use fuel ethanol (E85), diesel, methanol, leaded
fuel or any other 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 additives.
Note: Use of any fuel other than those recommended may cause
powertrain damage, a loss of vehicle performance, and repairs may not
be covered under warranty.
Octane recommendations
Your vehicle is designed to use
“Regular” unleaded gasoline with a
pump (R+M)/2 octane rating of 87.
Some stations offer fuels posted as
“Regular” with an octane rating
below 87, particularly in high altitude areas. Fuels with octane levels
below 87 are not recommended.
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 authorized dealer to
prevent any engine damage.
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 for vehicles
designed to use “Regular” unleaded gasoline because it may cause these
problems to become more pronounced. If the problems persist, see your
authorized dealer.
Do not add aftermarket fuel additive products to your fuel tank. It
should not be necessary to add any aftermarket products to your fuel
tank if you continue to use high quality fuel of the recommended octane
87
(R+M)/2 METHOD
Maintenance and Specifications
287
2010 MKZ (378)
Owners Guide, 3rd Printing
USA (fus)