Poor SL-6 Gas Mileage

Nice in a truc wish I got that mileage!. I have 87 318 in a W150 barely break 10! And the gas gauge is gone. I have 32 gallon gas tank fill it every 200!

Its in a w150 it gets 14.5 every tank.
If it makes you feel better I have a 2017 6.4 hemi that gets 10 mpg driving the same roads.
It sucks fuel down so fast it just sits in the driveway, it has only 3800 miles on it, a super thirsty vehicle.