CM 871 getting 3.6 MPG

[Rawze]

(06-18-2022 )Steel Dragon09 Wrote:  Turns out #6 exhaust manifold gasket had small leak. The one behind the heat shield that makes it easy to spot (sarcasm). I changed the entire manifold and now get between 4 and 4.2 mpg with my 3.9 rears heavy foot (65-70mph) and average gross of 117,000 lbs.

stop driving it so fast and learn to drive it by your boost gauge, selecting a better gear so that you can keep your boost down to 20-psi or so in a pull. - Otherwise, your own right foot is that thing that is your worst enemy, it sounds like to me.