Just for fun I tried a little hyper-miling experiment on my last fill up ($3.79/gallon Chevron, SoCal). Here are some of my results. I'd like to hear from you all if you've tried this.
Currently 1030 miles on the odometer. Truck is about 4 weeks old.
R/T commute is 60 miles 90% highway. Starting point was 22.5 MPG after a WE of towing a trailer. Commute includes a long climb and a long downhill in both directions.
On the flats I'm trying to push the instantaneous readout to between 22 to 60 MPG, keeping it, on average, around 40 MPG. Cresting over the hill (about a 4 mile down grade), I switch to neutral for the ride down, topping the instantaneous at 99 MPG.
Just for fun, on the way back over the hill I decided to cut the motor (turn key off), and discovered to my surprise the power-assist steering and braking were not affected. At the bottom, the motor was restarted and I continued on until arriving home. BTW, if the headlights are set to auto, and the engine off, the headlights will turn off after 30 seconds. Went to manual headlights.
So I cruised about 4 miles downhill with motor turned off completely and in neutral. After less than three days I went from 22.5 (starting) to 27 MPG average.
I'm not sure if cutting the motor has any detrimental effects on the drivetrain. Not so sure I'll make a habit of it though.
I have a little experience at this with my Ford C-Max hybrid and consistently get 43 MPG.
What do ya'll think?