[weaponxxx]

Urgent advice needed on fuel consumption:
I have a F25 X3 2012 Xdrive2.0i N20 engine
The FC on the car for a full tank of city driving is around 6.5km/l - 7km/l which I think is really bad.

When I accelerate, on the Efficient Dynamics bar cluster and the, acceleration always runs around 3km/l - 3.5km/l and the number changes every time the gear shifts up to 10 - 20km/l (which I think there may be some error) and can go up to 99.9km/l when braking.
Referring to the iDrive fuel consumption bars, traveling on a highways runs me an average about 12km/l but declines to below 7km/l once I am back in the city. The screenshot below shows town driving.

FC does not change in ECO or COMFORT mode as I have tested it for a few months on same routine driving (90% town/city drive)

I have asked a BMW specialist to check during a full service but they said no issues. I asked if it could be a O2 sensor or ECU needs to be remapped and they said no error codes related. I am not sure if this is unrelated but the fuel tank indicator does not indicate full tank of petrol after a fill up, it takes about 45 mins before the meter reads correctly after a full fuel pump.
Is this normal? How do I improve FC?

[383vett]

You need to run a full tank of gas and figure out consumption based on actual mileage divided by fuel used. You can't go by the car's computer calculations

[weaponxxx]

it's about 6.8km/l for a full tank for 90% city drive. is that good or bad? how do i improve it if it is bad?