3000 rpm or lower
From my experience you get the best gas mileage when you are in the highest gear and your rpm is low, around 1500 to 2000 rpm.
Generally speaking 90 kph (60mph)
Currently, the Honda Insight provides the best mileage with the estimated annual fuel cost being at $405. The second best vehicle that provides the best mileage is the Toyota Prius. These results were discovered by government tests.
It is a high gear which delivers the best gas mileage at higher speeds by reducing the engines's rpm's.
Driving on lower RPM's will reward you with higher gas mileage in addition to putting less wear on the engine. So, low RPM will be cheaper in the long run.
depends on what car and what engine, typically if your cruising on a freeway, you will be running at half RPM or at the most 3/4, but the lower RPM the better with that you get better gas mileage.
you are suppose to change at 3000 rpm to get your correct gas mileage
yes driving at a speed where the engine is running with a slower RPM then a speed where it is running at faster RPM will save a little fuel.
The MPG-o-Matic Gas Mileage calculator is the latest and greatest when it comes to specifically looking for gas mileage.
According to AAA the best gas mileage calculator is their own. The AAA gas mileage calculator is easy to use, and very accurate for the customer to feel safe in the miles driven on a certain amount of gas.
It provides a little more power by changing the transmission shift times to a more aggressive setting. For instance if in normal mode it may shift at 3,500 rpm. With the ECT in power mode, it would probably shift at 4,000 rpm or 4,500 rpm. Setting the ECT to power will however lower your gas mileage.
It obviously depends on the cars being compared but generally Diesel provides better gas mileage.