Cng And Lp Fuel System Modifications; Methylcyclopentadienyl Manganese Tricarbonyl (Mmt) In Gasoline; Fuel System Cautions - Jeep GRAND CHEROKEE 2023 Owner's Manual

358 TECHNICAL SPECIFICATIONS
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 gasolines 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 emission 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 or not the
gasoline contains MMT.
F S
UEL YSTEM
Follow these guidelines to maintain your vehicle's
performance:
(MMT) I  The use of leaded gasoline is prohibited by law. Using
N
leaded gasoline can impair engine performance and
damage the emissions 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 authorized dealer for service assistance.
C
AUTIONS
CAUTION!
(Continued)
CAUTION!
 The use of fuel additives, which are now being sold
as octane enhancers, is not recommended. Most of
these products contain high concentrations of meth-
anol. Fuel system damage or vehicle performance
problems resulting from the use of such fuels or addi-
tives is not the responsibility of the manufacturer
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.