For towing and very heavy payloads, premium is recommended in the 2018 F150. For day to day driving, I am comfortable using 87 octane in the Gen 2 EcoBoost with the dual fuel injection. For the Gen 1 motor in the SHO, we still error on the side of caution and run premium.

 

The 2015 trucks only had Normal, Tow/Haul and Sport as modes. How exactly were you using the Eco mode?

 

 

@<-KJP-> Thanks for pointing that out.. So I used ECO mode ONLY on the 2018 before the wreck at 9733 miles. Most of my driving up to that point was local , shall we say within a 25 mile driving radius of home. I am not a heavy footed driver with respect to take offs from lights or stop signs. We made one and half trips to Michigan with that vehicle with a normal round trip racking up 1000 miles. On the interstate I would normally select ECO mode as it seemed to be less aggressive with the adaptive cruise control (ACC)system. As you may know, with the ACC one has a tendency to get behind someone going slightly slower than one's set point and stay there. At least that was my problem. When I would move to the left lane the vehicle would downshift several gears to reach its set point. Normal speed on the interstate is best defined as limit plus 2 mph. Local, out of town driving is defined about the same Limit + 3mph to get the transmission to shift into 10th. In town I don't think I switched to ECO mode all that much.
The first 500 miles I used only the normal mode as the system learned my driving habits. After that I wished a I could change the driving mode default to ECO.

I wish I had recorded more of my usage with the 2.7 and the 10 spd. combination.

 

I found ECO mode is great for icy or slippery driving conditions because it puts such a delay on the acceleration. The wheels don't spin as much in ECO.
That's the only time I'll use ECO though.