New(er) Dodge aka Ram trucks.

2014 ram 3500 6.7L dually full delete, travel 40 miles to and from work and with traffic 5 days a week and some driving on the weekends, I fill up every 2 weeks. Get around 24-26 mpg on the freeway with traffic, open freeway, can go from south Idaho to south Cali with 2 tanks.