16! lucky! I wish! Only getting 14.4 mpg here...

 

We are getting 18MPG on my wifes 01 Burban, really depends on if its 2 wheel drive or 4 wheel drive. 2 wheel yes its def. possible, 4 wheel absolutely not possible

 

You guys in the 1500s are getting less than 20 mpg on the highway? I don't feel bad about my 2500 with the 8.1. I get 14 on the highway if there is no headwind. I use Lucas in all my vehicles when I remember. To get the best outcome you need to add it on a consistent basis.