Hard to know how accurate user reported numbers may be. Too many variables, not to mention most reports are from the notoriously inaccurate computer readout. Few vehicles match their EPA ratings which for an unloaded 2015 F-150 4x4 Crew Cab with the 3.5L Ecoboost is 17/19/23. Fuelly reports a 16.5 mpg average for 31 2015 F-150s with the 3.5L although options are unknown. Consumer Reports averaged 16 mpg.CALIcamperdad said:
A truck camper is bound to affect fuel economy, probably by at least 3 mpg. Turbo gas engines are all about fuel economy in normal driving with ample power for occasional needs. They work well for that. I have had two small displacement turbo gas cars and loved the performance combined with economy. However, conventional wisdom is that they are not meant for continuous heavy loads no matter the vehicle's max payload. Turbos gulp fuel and generate heat. Get a diesel or big block gas engine for heavy duty use. Has Ford made some magic to create a small turbo gas engine that can endure continuous loads and still return good mpg? By all tests I have seen the answer is no. Most Ford forum users report no better than 14 mpg with the Ecoboost when towing or with a truck camper, often more like 11 mpg. That might be slightly better with a small pop-up like the Hawk.
Note that Ford recommends the HD payload option for a slide-in camper, and they do not recommend a slide-in camper on any Crew Cab F-150.
