Most likely cause of fuel gauge being inaccurate?

I've got a cure for ya; keep your tank full like your supposed to.

If you want to know the secret:

#1 Fill it up AND a spare 5 gallon can.
#2 Take note of the odometer.
#3 Take a trip on the highway.
#4 Run out of gas.
#5 Take note of the odometer. That's how many miles you can float on a tank, freeway.
#6 Fill it up with 5 gallon spare, then drive to a filling station, re-fill and drive home.

If you really want to be a pimp, do this in stop and go: daily grind, this is your city mileage.

Even when new these gauges are ballpark at best. Don't trust them.



Also, consider a wideband o2 sensor so the A/F ratio is correct.