08 GMC CCSB. Front leveling kit only, 305/50/20 tires(actual height is 32")

Best tank on highway 14.8
Avg highway 13.9
Avg local 12

Hauled my motorcycle trailer today and got 8.2 MPG. It only weighs 4000 loaded. My 06 silverado with a 5.3 got 10 MPG everytime on the same trip, same trailer.

Diesel fuel 3.399 gal = very expensive and disappointing.

All mileage figured by GPS and amount of fuel pumped at the station. The DIC shows worse mileage than actual.

KD ECM on the way. Hopefully it helps