Gary Brown explains how turbo diesel tractor engines can be installed in pickups and how they can get up to 40 miles per gallon and run up to 100 miles per hour. These trucks can run on diesel or biodiesel. They burn diesel much more efficiently and therefore get up to triple the miles per gallon. This was done by testing and by trial and error. A good mechanic could do the same for your vehicle to help improve mileage.