Cng And Lp Fuel System Modifications; Methylcyclopentadienyl Manganese Tricarbonyl (Mmt) In Gasoline; Fuel System Cautions - Jeep GRAND CHEROKEE L 2021 Owner's Manual

CNG A LP F S
ND UEL YSTEM
M
ODIFICATIONS
Modifications that allow the engine to run on
Compressed Natural Gas (CNG) or Liquid Propane
(LP) may result in damage to the engine,
emissions, and fuel system components. Problems
that result from running CNG or LP are not the
responsibility of the manufacturer and may void or
not be covered under the New Vehicle Limited
Warranty.
M
ETHYLCYCLOPENTADIENYL
M T
ANGANESE RICARBONYL
G
ASOLINE
MMT is a manganese-containing metallic additive
that is blended into some gasoline to increase
octane. Gasoline blended with MMT provides no
performance advantage beyond gasoline of the
same octane number without MMT. Gasoline
blended with MMT reduces spark plug life and
reduces emissions system performance in some
vehicles. The manufacturer recommends that
gasoline without MMT be used in your vehicle.
The MMT content of gasoline may not be indicated
on the gasoline pump; therefore, you should ask
your gasoline retailer whether the gasoline
contains MMT. MMT is prohibited in Federal and
California reformulated gasoline.
F S
UEL YSTEM
Follow these guidelines to maintain your
vehicle's performance:
The use of leaded gasoline is prohibited by

Federal law. Using leaded gasoline can impair
(MMT) I
N
engine performance and damage the emis-
sions control system.
An out-of-tune engine or certain fuel or ignition

malfunctions can cause the catalytic
converter to overheat. If you notice a pungent
burning odor or some light smoke, your engine
may be out of tune or malfunctioning and may
require immediate service. Contact an autho-
rized dealer for service assistance.
C
AUTIONS
CAUTION!
(Continued)
TECHNICAL SPECIFICATIONS
CAUTION!
The use of fuel additives, which are now being

sold as octane enhancers, is not recom-
mended. Most of these products contain high
concentrations of methanol. Fuel system
damage or vehicle performance problems
resulting from the use of such fuels or addi-
tives is not the responsibility of the manufac-
turer and may void or not be covered under
the New Vehicle Limited Warranty.
NOTE:
Intentional tampering with the emissions control
system can result in civil penalties being assessed
against you.
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