Jeep 2009 Compass - Owner Manual - Manual (Page 310)

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 (with the ap-
propriate octane rating for your engine) before consider-
ing service for the vehicle.
Reformulated Gasoline
Many areas of the country require the use of cleaner
burning gasoline referred to as “reformulated gasoline”.
“Reformulated gasolines” contain oxygenates and are
specifically blended to reduce vehicle emissions and
improve air quality.
The manufacturer supports the use of “reformulated
gasolines”. Properly blended “reformulated gasolines”
will provide excellent performance and durability of
engine and fuel system components.
Gasoline/Oxygenate Blends
Some fuel suppliers blend unleaded gasoline with oxy-
genates such as 10% ethanol, MTBE, and ETBE. Oxygen-
ates are required in some areas of the country during the
winter months to reduce carbon monoxide emissions.
Fuels blended with these oxygenates may be used in
your vehicle.
CAUTION!
DO NOT use gasolines containing Methanol or E85
Ethanol. Use of these blends may result in starting
and drivability problems and may damage critical
fuel system components.
Problems that result from using methanol/gasoline
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.
308 STARTING AND OPERATING