"Boolean" fuel efficient throttle
 

I was thinking about another way to automate (partially, anyway) the fuel efficient driving process. Previously I'd been considering a cruise control model. Most of my effort goes into getting the right throttle position given the terrain. What if there were a mode (separate from the pedal is what I'm thinking so you can still easily get unambiguous total control) that just put the car in the most fuel efficient throttle (using info from the OBDII port)? When and where to use it would still be manual. The "try to drive like you have no brakes" tip is what got me thinking about it. This would be more like "try to accelerate like all your engine will do is the most efficient speed".