Your vehicle was not designed to use fuel or fuel additives with metallic
compounds, including manganese-based compounds containing (MMT).
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 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.
If there is a “Premium Fuel
Recommended/Required” label in
the fuel filler door area, your vehicle
is designed to use “Premium”
gasoline with an (R+M)/2 octane
rating of 91 or higher for optimum performance. Gasolines with lower
octane ratings can be used, but performance may decrease. We do not
recommend the use of gasolines labeled as “Premium” in high altitude
areas that are sold with octane ratings of less than 91.
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.
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 (particularly
in the United States) because it may cause these problems to become
more pronounced. If the problems persist, see your dealer or a qualified
service technician.
The American Automobile Manufacturers Association (AAMA) issued a
fuel specification to provide information on high quality fuels that
optimize the performance of your vehicle. We recommend the use of
fuels that meet the AAMA specification if they are available.
It should not be necessary to add any aftermarket products to your fuel
tank if you continue to use a high-quality fuel.
87
(R+M)/2 METHOD
91
(R+M)/2 METHOD
Maintenance and care
178
Summary of Contents for 1999 Navigator
Page 146: ... Front 4x2 Front 4x4 Rear Roadside emergencies 145 ...
Page 204: ...4 1 3 5 2 Capacities and specifications 203 ...
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