On interstate with the cruise set and in overdrive it absolutely gets 29 mpg. It's been checked numerous times. It gets 23 mpg driving through the mountains from here to Branson, MO. We make that trip every August.
Everyone tried to get me to reflash the computer. I'm very glad that I didn't.
Daaaaaaaaaaaaaaaaaaamn.......thats awesome.
I have an 03 durango with the 5.9 and 3.91s.....its 4x4 (part time) too......I only get maybe 15 if I am lucky on the highway, cruising, all flat.......of course my Durango has the aerodynamics of a cinder block....LOL
My 92 Dakota has the (first) magnum 318 and it gets around the same.....11 around town, 15 highway....
Of course I drive both like I stole them....
Still, you are getting TWICE the mileage.
That is a sweet setup dude.
Do you have pics of the install?