Lincoln 2007 Mark LT Owner's Manual page 278

If you do not use the proper fuel filler cap, excessive vacuum in
the fuel tank may damage the fuel system or cause the fuel cap
to disengage in a collision, which may result in possible personal injury.
Choosing the right fuel
Use only UNLEADED fuel or UNLEADED fuel blended with a maximum
of 10% ethanol. Your vehicle was not designed to run on E85 fuels that
are blended with a maximum of 85% ethanol. The use of leaded fuel is
prohibited by law and could damage your vehicle. Do not use fuel
containing methanol. It can damage critical fuel system components.
Your vehicle was not designed to use fuel or fuel additives with metallic
compounds, including manganese-based additives. Studies indicate that
these additives can cause your vehicle's emission control system to
deteriorate more rapidly.
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
pump (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 authorized dealer to
prevent any engine damage.
Fuel quality
If you are experiencing starting, rough idle or hesitation driveability
problems, try a different brand of 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
2007 Mark LT (mlt)
Owners Guide (post-2002-fmt)
USA (fus)
Maintenance and Specifications
87
(R+M)/2 METHOD
277