Just returned from my annual trip to the Florida panhandle area with my V6 OL 4x4. I've done this trip at the same time of year for about 15 years now, so was interested to see how the WK2 would compare. These are all computed figures from fuel receipts; not EVIC figures.
These are not attempts at best mileage, just what I got using my long distance highway norms: 75 to 85mph when traffic and smokies allow, which was most of the time, otherwise go with the Interstate flow. The mileage is about 98 percent highway, since I had another vehicle to share driving duties once in FL. Car loaded with gear. My WK2 has had the recent ESC and PCM/TCM TSBs applied.
Distance: 4,998 km (3,106 miles)
Mileage: 10.17 L per 100 km
27.8 mp Imperial gallon
23.1 mp US gallon
This is 10 percent better that the very best I ever did on the equivalent trip in my old XJs with 4.0L in-line 6 engine (and 15 percent better than that old vehicle average).
Not the 32 mp Imperial gallon which Chrysler claims the V6 can achieve on the Canadian highway mileage test, but if my foot was lighter it might be just possible.
Factor in the huge upgrade in comfort, quiet and yes, even power, and I like it!