Choosing The Right Fuel; Octane Recommendations - Ford Explorer Sport-Trac Manual Del Usuario

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% ethyl alcohol. Your vehicle was not designed to run on E85 fuels
that are blended with a maximum of 85% ethyl alcohol. 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. In Canada, premium grade fuel generally
contains more metallic additives than regular grade fuel. We recommend
using regular grade fuel. In Canada, many fuels contain metallic
additives, but fuels free of such additives may be available; check with
your local fuel dealer.
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.
2007 07+ Explorer Sport Trac (esp)
Owners Guide (post-2002-fmt)
USA (fus)
Maintenance and Specifications
87
(R+M)/2 METHOD
299