Just to throw in my 2 cents, I feel your pain. But I've got an 8 inch lift on 37s. Egr delete, coolant filter and the blue spring kit are the only things done to the motor. I've got an sct livewire ts tuner that I usually leave on street mode. I get about 11.5 mpg it's the nature of the beast bud. I came on here hoping to find some answers but apparently that's the best I'm gonna get and I'm ok with that. The truck looks great, hauls my 15k pound truck and trailer when I need to and turns heads all day. Worst case, pull the fuel tank and clean it and make sure your sending unit isn't clogged up. Good luck

 

Are your doing mpg by hand or monitoring? 37's will screw big time....I've spent whole lot of time and money try and truck figure out why a 6.0 Excursion 18+ mpg vs roughly 15 mpg for Superduty.

It's a lot of little thing to get to close the Excursion...I'm still not sure it's not a behavioral change. Ours is raised 5" leveled and 1.5" taller tire, 4wd...lately we've getting 18 mpg or within fractions in warm weather if we stick to 65mph on pancake roads...even light trailer fishing or quad. When the RPM's get much over 1,750 it's roughly 1-2 miles per 1,000 rpms in lost mpg....all depends load and road.

 

Oh the mpg gauge in the truck is way off lol I do it by hand. It is what it is. Honestly I need to get an after market fuel pump to keep up with the programmer and clean my fuel tank. Just haven't had time to get around to it.

 

Dang,im jelouse every one of you with those mpg numbers.

 

My 03 got 19 to 21 MPG highway when new, if I kept my foot out of it, settled in to about 19 MPG average at about 10K miles. Then Ford updated my computer strategy, (as a free service to me for being a such good customer, only time they ever saw my truck) after the reflash I was getting 11 to 14 MPG combined city highway and 8 to 9 MPG towing heavy. Dealer said it was impossible to reflash back to older strategy. I finnally was able to get the ECM and FICM rolled back to a better strategy and now I get about 18 MPG average highway and 10 to 11 MPG towing heavy. You need to find out what strategy your truck has and talk to someone like ED@FICMREPAIR, they do rollback programing.

 

mines 9.5 towing heavy, i realy dont know what it gets empty, never disconnects from flatbed, im going to try that motorcraft cetane boost.

 

Those numbers are pretty horrible - I'd be surprised if a rollback and/or FICM tune couldn't help you out.

Thanks for the referral JetJockey!

 

mines got the vxcf4 flash now