Accuracy of low gas icon and miles to go display

[slingshot]

When I bought my car, the gas tank was full and the estimated distance to empty read 285 miles. My gas gauge was real close to E when the low gas icon finally came on. The estimated distance to empty was about 15 miles and I had driven about 310 miles of which about half were highway and half city.

When I filled the tank, it only took 14.7 gallons to fill. That meant almost 4 gallons were left when the low gas icon appeared and the gas gauge was close to E. The estimated miles left on the tank must have meant only when driving till the gas gauge reads E. Obviously then, the gas gauge must dip below E while using up the 4 gallons left.

When my car was full again, the estimated distance to empty again read 285 miles. Is this a fixed value and is anyone else getting same numbers every time like me? Maybe it takes worst case of 20 mpg and then adjusts if you get better mileage.

Anyone else see similar gas accuracy strangeness?
Dave

[MGLax13]

Well it is an estimated value, so they probably take the average MPG value and multiply that by the size of the tank.

[fotodad]

I've gotten the "estimated to empty" reading down to eight miles. When I filled up my car took about 15 gallons. So I think you are right about there being more gas in the tank than what the indicator shows.

I've also noticed when filling up that I can put an additional gallon to two gallons of gas in the tank after it automatically shuts off at the pump.