Choosing The Right Fuel; Octane Recommendations - Ford Explorer 2008 Manual De Instrucciones

Maintenance and Specifications
The fuel system may be under pressure. Insert the fuel filler
nozzle slowly; otherwise, fuel may spray out and injure you or
others.

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.
368
2008 Explorer (exp)
Owners Guide (post-2002-fmt)
USA (fus)
87
(R+M)/2 METHOD