over time I've found that every vehicle we have owned (there are 5 parked in the driveway right now) has speed (sweet spot) where it gets the best mileage .... for most it has been the lowest speed at which the automatic transmission (haven't owned a straight drive since '78) is in OD/highest gear and has sufficient torque to prevent transmission changes on minor grades .... as one example, the Allison transmission shifts into 6th gear at 58 - 59 mph in our Freightliner Sportchassis .... if I set the cruise at 61 - 62 mph she gets the best mileage .... I'm not talking about what speed it will undergo mileage certification, with its 3-cylinder engine, I wonder what the operational sweet spot for mileage in an Elio will be ...
Jim
Jim