Originally Posted by TomB1269
New Member, just bought mine in March, currently at 2200 miles. Its the 5.7 quad cab I have been noticing that my hand calculation is usually 1/2 to 1 mile per gallon less then display reads. I reset at each fill up and do not touch it until the next one. (I have always calculated my fuel mileage, it's a great way of knowing what's up in the motor)
Anyone else notice this discrepancy? I am wondering if the mileage display is dead on but the speedo is off as with nearly every vehicle built today. They all run at least 2 to 4 miles hour slower than the speedo reads.... Check it for yourself and it does not matter brand, age, tire size, etc. and its what mkaes the MPG calculation of on the dash??
Yes, the EVIC display on our truck right around 10-12% optimistic.
The same was true with out '16 Subaru also, and from what I've read on Subaru forums that seems to be routine as the factory setting, but with that vehicle there is a way to adjust the calibration up or down by percentage points, and now it's pretty close to right on.
There is no calibration adjustment on RAM trucks however, which is too bad really - it would only be a few lines of code to implement.
The speedometer seems to be just about right on the money however, judging by both those roadside "your speed is xxx mph" radar checks and also by actually setting the cruise at 60mph and timing the milepost markers as they go by. The speedometer on our Subaru is equally accurate, so I think it's the fuel consumption displays that are off from the factory. Maybe even deliberately so, just to make people feel like their vehicle is more frugal with gas than is actually the case.