Noob Honda Accord Ex-L V6
 

Hi, all!
I just bought this car and it's the first I've had with on board fuel calculation.
The first tank?
On board calculation 28.8
Calculation by hand 26.5
Dismayed to say the least. Anyone else with a mileage discrepancy this large?
Tia

In very rare cases the dashboard display is dead on. In most cases it actually overestimates the mileage. My FEH's dash display usually overestimates my mileage by about 2 MPG. It may be able to learn your driving and fuel use habits, and get more accurate with use, but don't bet on it. Use the dash display as a rough estimate, but never rely on it to be accurate.

Thanks, Jay. Hard not to be cynical, right?
Sure looks like a deliberate overstatement of gas mileage by the car makers.
By the way, the EPA mpg overall for this car is 26, exactly what I'm getting.
I'm also wondering if the on board gas mileage indicator is responsible for so many internet accounts of this car attaining 30 mpg average.

Most average folks take that dash readout as Gospel, and never double check it. Plus, a difference of 2 MPG isn't likely to be caught unless someone actually keeps mileage records and compares it to the dash display. If the display says 30, and the car is getting 28, its not likely to be caught by the casual observer. If the display says 30, and the car is only getting 25, just about anyone will catch it, even if they don't do the math.

As mentioned, most on board computers are optimistic, my readout is generally 2 to 3 MPG higher than actual, it's only an indication. I tend to find though, the longer the trip, the more accurate it becomes, after say 300 miles or so it averages out.

When I record a fillup here, I always note the dashboard reading in the "Notes" section, so I can have a record of the discrepancy.

I find the on-board estimate is almost always about 1-2 MPG optimistic.

Great idea, thanks.