My truck has an auto so it's not quite the same. Before chipping I got about 10 mpg towing. I did the DP Tuner with some other mods and have been really happy with it. My mileage went up about 2+ mpg unloaded and towing. I tow a lighter trailer, (about a ton less) but I normally get about 12.5 towing when I top out at 65. If I get my speed down to 55 it really surprises my...about 14+ mpg without any steep hills. Speed makes all the difference. At $3.00 per gallon 55 seems a really reasonable speed to me. If I'm not doing hills I tow in econo setting and it runs great. When I'm doing steep hills I switch to the tow mode as it tightens up the tranny, just not quite as much power/ The mileage stays about the same.
Unloaded it gets about 23 mpg at 65.
Unloaded it gets about 23 mpg at 65.
