bad mpg what to do?

He means you can't talk about it on this forum.

 

|You might need go chang your fuel filter and fuel water separater if u have one. If you do have one make sure the bowl isn't cracked and letting it suck air..

 

My neighbor has a 2013 cascadia with newer aero package, 13 sp, dd15 475HP, and 3.58 gear. He complains that his truck doesn't get 7 mpg but 5 mpg instead. He drives around 68 mph. My t600 gets 5.1 at 69 mph.

 

Yep, you can grind the fuel economy of any truck right into the ground with a heavy enough approach with the right foot.

 

So seriously; what are you saying, 60 mph or less, regardless of the truck. Asked with respect and sincerity.

 

It is physics... go faster, and the retarding force created by aerodynamic drag increases by the square of the velocity increase. If 5 mpg doesn't bother you or your bank account, then by all means go for it.

 

Sometimes road speed makes little difference. The load I'm currently on yielded 8.3 for the first 500 miles and 5.3 for the last 900. All of it at 58 MPH.

Edit: sometimes there's nothing you can do to make it better but plenty to make it worse.

 

My S60 won't run at 55mph in 13th. Runs well at 55mph in 12th at 1500rpm, but does that help my mpg? Runs ok at 60mph in 13th at 1350rpm but constantly downshifting for almost any incline. How would you advise?

 

What year S60? Late 90's early 2000's ran best @1450-1550. I had a brochure from that era that clearly showed the bottom of the fuel consumption curve at 1500. Most drivers will tell you that a Series 60 had a sweet spot around 1450-1500. That's pre EGR 12.7 only.