fuel milage????

[coalrollr]

hey guys i have a question that maybe yall can help me with my family has two 6.4s one is a 08 king ranch and the other a ext cab long bed they both have the same rearends and both totally stock except the ext cab has a afe intake. the king ranch gets a consistent 15.5 and the ext cab gets a solid 10 what could be wrong?

[countryraised]

do they get the same driving or is the ex cab more of a work truck, loaded more? maybe the ex cab gets driven with a heavy foot?

[Capt dong]

different drivers
bad fuel
lack of maintenance
hand calc?
different roads
weather
intake throwing codes
loads
longer bed creating more drag