-airing up the tires
-go 55 mph on freeway, maybe 60 max if someone is tailgating you
-take off unnecessary weight
-keep it at 4x2 mode
-Pulse and Glide when possible
-time lights/travel when theres less traffic
this should get it close to 20 mpg if not very close to that
Not much you can do to the 4.0L tractor engine but you can make the work load lighter. Regular Highway Tread Tires at higher PSI. No Lift. Remove any weight, including back seat. If you have a roof rack...take it off. Since the 4.0L puts out great torque at low RPMs, drive in the 1500-2500 rpm range.
2006 Jeep Liberty CRD...Founder of L.O.S.T.
OME 2.25" Lift w/ Toyo Open Country HTs 235/75/16s
ASFIR Alum Eng/Tranny/Transfercase/Fuel Skids
2002 Air Box Mod...Air Tabs (5) on Roof...(3)each behind rear windows
Partial Grill Block with Custom Air Scoop and 3" Open Catback Exhaust
Lambretta UNO150cc 4 Stroke Scooter