my 05- 6 speed- 33's with 3:73- just came in at 16mpg with mixed driving. i have hit 19 on mostly higjway. Some might not be aware the 6 speed has a low first which is more forgiving on the lack of gearing for getting going ...not to disregard the regearing conversation but depending on what you do you may not want to go as low?
. I do find staying down a gear is more beneficial, although as an example the engine can motor down the road in 6th at 50 mph it takes less throttle to be in 5th for you that maybe 4th so keeping the cruising rpms in the mid 2000 range should help.