Hello everyone, Rick here.
Vehicle in question is an 04 silverado 5.3l.
If you are going down the road, level ground, steady wind, 50mph and shift from 4th gear to 3rd gear and keep the speed the same the instant MPG readout will dip down a bit for a few seconds, then go back to just about where it was in 4th gear.
Now I know those instant MPG meters are not 100 percent accurate and I also know there are many variables. It did get me thinking though, Is it theoretically possible to get the same or better MPG with the engine in a lower gear?
I know it makes no sense since manufacturers put taller gearing in vehicles for MPG benefits and also added OD transmissions and they didn’t do this for any reason other to save fuel. But are there some situation that you could have the same fuel consumption with higher RPM? I would think it would take more fuel to spin the engine faster, however there are so many factors I get confused.