Petrol Consumption?

[fender]

Is it true that petrol consumption of a car is more efficient the more the tank is full?

I have heard this, although, logically, it does not seem to make sense.

Can anyone confirm?

Thanks.

[AntiLochus]

If it's full of petrol the car is heavier, so logic dictates the engine needs to work harder to move that extra weight around.

:confused: