my 2008 has 405 miles so far: 12 mpg average but that is nearly all stop and go, very little steady highway driving........and yeah it better get better.
my 2004 4.7L H/O Limited got 17 mpg same conditions: very little highway.
2008 Grand Cherokee Limited 4X4, Light Greystone Pearlcoat, Hemi, Tow Group, 18" Chrome Clad Wheels. Original owner, 20,000 miles
2002 Wrangler Sahara, black, 4.0L, 5-speed, Dana 44 rear axle with Trac Loc LSD, duel tan tops, Canyon wheels with Wrangler Silent Armors. 75,000 miles, 2nd owner.