X2 on all of the above, especially the maintenance/tune status/mileage of the vehicle. What octane fuel is he using? He's located at over 6000 ft. elevation, and probably should be running 85 or 87 fuel, depending on mods., if any. Running higher octane fuel than needed is a waste of $$$ and can also reduce power output. Fuel economy at that altitude MAY be a little worse than those at sea level, because the engine is making less power. All the things mykdee311 said are particularly important.
06 GCO, Dk Khaki, QDII, Flshing Hi 3rd Bk Lt, MDS "ON" Lt, Airtab Vortex Gens, Debadged, Fumoto Drain Valve, BT Catch Can, Chopped EGR Tube, SRT8 CAI, K&N Filter, Sonnax Trans Line Press Booster, SC Tuner W/Adv Trans Tune App, DS Tuner, Cust tubular hdrs w/3 in Magnaflow/Xlerator AP Exh Sys, Bilsteins, SRT Springs/Sways, Cust Eng Cvr, SRT8 frt/rear bumpers, FRI Sidewinder Cam/6.1 valvetrain, SLP 25% UD Pulley, BBK true 90mm T-Body, SOS Ign Coils w/.060 spark plug gaps, SRT Reps with 265/45&295/40X20's.
Well he has a K&N drop in intake, synthetic oil Mobil 1, K&N oil Filter, New fuel filter, and thats about it, he is getting about 14.4 according to the on board computer, the jeep just rolled 89,000 miles, the jeep has been babied since he has owned it looks and drives nicely, at least from what we can tell, honestly dont know a lot about these kind of jeeps I am an XJ and TJ person, he Runs 85 Octane
If he lives out in the mountains of Colorado, like your location says - I'm not sure his mileage will get much better. Things I would check? fluids, tires, alignment, spark plugs, airfilter (if it's filthy) Things to look into. Hypertech Max Energy Programmer, AirRam Power Wire, Ported Throttlebody.
Where and how you drive will affect your mileage as much as the other stuff. I drive 4 miles each way to work and back and I get 10 MPG. Yes I use 18 gallons in 180 miles.And my computer says I get 10MPG average. Here's the break down....4 miles, 16 traffic lights/ stop signs, long traffic lights, waiting at drop off zone at elementary school. Virtually no highway miles to improve average. If you get 12 to 14... be glad not sad
05 Grand Cherokee Limited 5.7 Hemi 265/65/17 Revos, K&N
HEMI CLUB MEMBER #10
1998 ZJ Special Edition 2wd- Traded
1991 XJ 2.8 2wd Sold