This is exactly what I did. It has kind of retrained me to drive when in the truck! I guess I never really realized how much gas my heavy foot was using!!

 

I just traded my 2013 5.0 in on a 2015 3.5 Ecoboost. My 5.0 was leveled with 33's on it. it did not matter how I drove it; highway, city, drive like a grandma or drive like I stole it, 15mpg.

 

3600 miles on my 2015 5.0 Crew 4X4. 16.1 mpg average over lifetime. I manually calculated 16.3 over that same period. Only been on the interstate once for about 250 miles. Rest is city/low speed driving.


I see higher numbers over the display over short trips, but I don't believe them, because the long term average comes up lower and matches what I calculate manually. Lifetime average or average mpg over 2500+ miles usually tells the real story.

 

Low speeds equals less drag. That's why you have such great mpg's.

 

I've got 1000 miles on a supercrew xlt 5.0L. I was getting good mileage using the little digital readout but quetioned it on a trip this weekend, about 400 miles total, I calculated the mileage by hand logging my fill-ups. Going from Maine to NY with part of the trip over the VT green mountains, my mileage was 21.8 mpg. A big cry from my 2003 silverado v8 at about 16 mpg.... Oh, and it seems to coincide with my digital mileage readout the truck does.