Gas mileage

You can open the tailgate and secure a small load with straps to save gas. Some people believe that keeping the tailgate closed and the bed open, the wind creates a suction that picks up on the back of the truck to take weight off and that saves gas but honestly different vehicles are different. If you go with a bed cover, get something that's light because a heavy fiberglass cover can hurt your gas mileage.

I doubt you will save money. There was an aerodynamic study that showed that leaving the gate up is best.

Read this. A bed cover might gain you 0.1 mpg. https://www.motortrend.com/news/truck-fuel- economy-improvements/

I have a 2006 54 the mileage drop to 8.3mpg I read the blog that said replace injectors, then the coils same, air intake,oil, air in tires, fuel filter with no improvement then I remove the fan clutch, installed a electric fan, so far the mpg has went up 6 mpg. I hope this help others!