which pick up has the best fuel efficiency. I am looking for a F250 or copareable truck, gas fuel. I have a Titan 5.6 gas. it gets no better than 15mpg with no load. Can you believe it. It is rated for 15,100 gvw which includes a trailer load. It pulls fine with a fifth wheel but the mph just isn't good enough. Nissan should be ashamed of that product line.