On long trips, I optimize speed to road and traffic conditions, as everyone does, but also to engine RPMs. If speeding is making you run 4000 RPM in your highes

On long trips, I optimize speed to road and traffic conditions, as everyone does, but also to engine RPMs. If speeding is making you run 4000 RPM in your highest gear, you might want to slow down a bit (use your onboard MPG display to see the difference). Someone can check whether the time savings of having to make fewer stops for gas is worth it. The fuel consumption and engine wear savings certainly seems good to me. Update: There is also aerodynamics to think about. Aerodynamic drag is almost twice as great at 70mph as it is at 50mph.[1] [1]http://craig.backfire.ca/pages/autos/drag http://craig.backfire.ca/pages/autos/drag