What Car Q&A - How can I check fuel economy figures?

Q: I don't believe I'm getting the fuel consumption figure that my car's trip computer is claiming. How can I check the car's fuel consumption accurately?
Dennis Wareham

A: You need to start a detailed fuel log. To do this, you need to:

1. Fill up your tank to the brim.
2. Drive until the car's fuel tank is a quarter full or under and record the amount of miles completed.
3. Fill up again, measuring exactly how much you took to fill it up.
4. Drive until the car is a quarter full or under once more.
5. Fill up again, recording exactly how much fuel you used and how far you have travelled.
6. Take the total number of litres you have used and divide this figure by 4.5461 to calculate the total number of gallons used.
8. Divide this figure into the mileage to find out your total mpg.

This should give you as accurate a picture as possible of the amount of fuel your car is using.