Why is my car's fuel reading so incorrect?

2016 Ford Focus, fuel efficient readings after a couple weeks go all the way to 99.9 MPG no matter how I drive, and on the estimated fuel left, it's used up at a rate of almost 5 miles to 1 actual mile, Yesterday I left the house to go grocery shopping and it had "100 Miles to Empty" and I drove a 5.4 mile trip twice, and when I got back, "60.6 miles to empty". It's the SE Sport model. Any help is greatly appreciated

2016 Ford Focus, fuel efficient readings after a couple weeks go all the way to 99.9 MPG no matter how I drive, and on the estimated fuel left, it's used up at a rate of almost 5 miles to 1 actual mile, Yesterday I left the house to go grocery shopping and it had "100 Miles to Empty" and I drove a 5.4 mile trip twice, and when I got back, "60.6 miles to empty". It's the SE Sport model. Any help is greatly appreciated Try resetting your fuel milage and trip computer. I have a 2014 and whenever the dealer resets mine it gives me outrageous numbers like this but after a few days of driving it usually resets to around 32mpg your car does not get 99.9 miles per gallon 2016 ford focus get the following MPG: Up to 30 city / 42 highway Bad sensor. I've never met anyone who would do anything but ignore it. Even when they work, they're not very accurate. Instantaneous mileage readings are completely meaningless and you should not even look at them.

Your car does not get 99.9 miles per gallon 2016 ford focus get the following MPG: Up to 30 city / 42 highway

Bad sensor. I've never met anyone who would do anything but ignore it. Even when they work, they're not very accurate.

Instantaneous mileage readings are completely meaningless and you should not even look at them.