Originally Posted by suss6052
Ford deliberately made it an average mpg display in the trip computer, there is no code for it to calculate an instant mpg on Focus Models sold in North America.
It appears that while it might start off nearer to where it was before it tends to have to think about it first starting from a lower number as its sample size is too small to give an accurate reading until eventually stabilizing somewhere near the steady state condition.
I am not looking for a real-time instantaneous display. I am quite fine with the fact that Ford chose not to have an instant MPG mode, as I think they are useless.
Are you saying that the car, internally, does not know how much fuel it is injecting and what speed you are going? That is impossible.