dude...I just got back from a trip to PA racing, had 4 people in my truck, with the big tires, and 5.4L, towing a 3 ton trailer through the mountains. I averaged 9mpg. And I get 15-16 normally. SOMETHING ELSE IS WRONG WITH YOUR TRUCK OR THE WAY YOU OPERATE IT
Youll save gas money wich will pay for ur oil and a programmer in the long run. Sent from my SCH-I500 using Tapatalk
Try cleaning your MAF and TB. I did this and my gas mileage went from around 12 to just under 15 strictly city driving. Something has to be up because 9 MPG isn't right. Do you have bigger tires?
It doesnt matter if youve used it in all your past trucks, or your uncle used it in his gyrocopter. Its not meant for a gasoline motor. diesel oil is thicker, you will damage the oil pump , and rot out seals faster. the oil pumped is made for thinner gasoline motor oil, its not rated for a heavier oil. diesel oil has a higher ZDDT content and will plug up the cats. And it has a higher scrubbing agent that will remove deposits from the cylinder walls that actually help seal the combustion gases. You should put diesel fuel in your gas tank.... its the same thing, Ive been running it in every truck ive had.
I have the 4.6, a k&n filter, e fans, a bed cover ( i think it helps), and a gryphon and I get 15.5 on average turning 35s on 20s with a 6" lift.