s are not made to be "accurate" or "Linear". They are simply a fuel level indicator. They are GENERALLY very repeatable. I have never, personally, owned a car that the fuel guage would read too low one time and too high the next, and I've only had one that would effectively run out of gas before the guage showed empty - and on that one (1995 Pontiac TransSport) it wasn't a guage issue. If I hit rough road (washboad) with lessr than 1/4 tank the bottom of the plastic tank would shake so much the fuel pickup sucked air, and the engine ran out of gas. Bleed the air out of the injector rail, and it would start right up and go another 70km or more on smooth roads. Most cars are set up to turn on the low fuel warning with a 20 mile or
30km "reserve". I had one that when it said empty it WAS empty, and one that would go 100km after the guage stopped moving below empty - but both were CONSISTENT that way.I DO zero my ODO at every fillup - and I DO watch the trip meter - but I watch the fuel guage to determine when I need fuel. My Ranger can give me 15MPG, or it can give me 27MPG - and that is a BIG difference in the number of miles I get on a tank!!!!!
Same with the Taurus. 22-34MPG depending on road conditions, fuel, speed, temperature etc, all on the same trip (3000 miles) over a 2 week period.