Question of the week: Why is the distance to empty figure on my car so inaccurate?
Fri, 23 Jan 2026
Dear Honest John,
"I have an MG HS petrol and since purchase I have had a issue with the miles in tank reporting incorrectly. e.g. I can do a motorway journey with the car showing 300 miles in the tank, travel 195 miles and the tank still shows 184 miles in the tank. MG have exchanged the fuel pump system to no avail.
The dealership has now advised me as follows: 'MG have come back to us stating that you can not go off the calculated mileage that the car has made at the start of the journey to the end mileage.
You will have driven the car in different driving styles, so the vehicle will recalculate the remaining mileage available in the tank for any journeys carried out. Ie Motorway driving at 60 – 70 mph, your mileage should count upwards due to fuel consumption.
As soon as you stop motorways or average speed driving the fuel consumption will drop and the computer will make a re-evaluation of your remaining mileage.
I hope this explains more of an understanding as to how the fuel consumption works.'
The question is, are they correct or am I being fobbed off?
- RT
Dear RT,
In brief, what the dealership and MG are telling you is correct.
The 'distance to empty' or 'miles remaining' display in any petrol or diesel vehicle is a calculation based on the current average fuel consumption and the quantity of fuel remaining in the tank.
At the start of your journey it will give you a figure based on these two factors, but how you drive and the type of roads you are travelling may then change your average consumption and therefore change the range remaining.
It is constantly recalculated and so should not be treated as an absolute, but rather a guide to how far you can travel on the remaining amount of fuel in the tank.
