Jeep Grand Cherokee 2013 Operating Information Manual page 277

FUEL REQUIREMENTS —
GASOLINE ENGINE
3.6L Engine
These engines are designed to meet all emis-
sions regulations and provide excellent fuel
economy and performance when using high-
quality unleaded gasoline with a minimum re-
search octane rating of 91. The use of premium
gasoline is not recommended, as it will not pro-
vide any benefit over regular gasoline in these
engines.
5.7L Engine
Theses engines are designed to meet all emis-
sions regulations and provide satisfactory fuel
economy and performance when using high-
quality unleaded gasoline having an octane
range of 91 to 95. The manufacturer recom-
mends the use of 95 octane for optimum per-
formance. The use of premium gasoline is not
recommended, as it will not provide any benefit
over regular gasoline in these engines.
Light spark knock at low engine speeds is not
harmful to your engine. However, continued
heavy spark knock at high speeds can cause
damage, and immediate service is required.
Poor quality gasoline can cause problems such
as hard starting, stalling, and hesitations. If you
experience these symptoms, try another brand
of gasoline before considering service for the
vehicle.
Over 40 auto manufacturers worldwide have
issued and endorsed consistent gasoline speci-
fications (the Worldwide Fuel Charter, WWFC)
which define fuel properties necessary to de-
liver enhanced emissions, performance, and
durability for your vehicle. The manufacturer
recommends the use of gasoline that meets the
WWFC specifications if they are available.
Besides using unleaded gasoline with the
proper octane rating, gasolines that contain
detergents, corrosion and stability additives are
recommended. Using gasolines that have these
additives may help improve fuel economy, re-
duce emissions, and maintain vehicle perfor-
mance.
Poor quality gasoline can cause problems such
as hard starting, stalling and stumble. If you
experience these problems, try another brand
of gasoline before considering service for the
vehicle.
Methanol
(Methyl or Wood Alcohol) is used in a variety of
concentrations when blended with unleaded
gasoline. You may find fuels containing 3% or
more methanol along with other alcohols called
cosolvents. Problems that result from using
methanol/gasoline or E-85 Ethanol blends are
not the responsibility of the manufacturer. While
MTBE is an oxygenate made from Methanol, it
does not have the negative effects of Methanol.
CAUTION!
Do not use gasolines containing Methanol or
E-85 Ethanol. Use of these blends may result
in starting and driveability problems and may
damage critical fuel system components.
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