Fuel Gauge Reading Off

[CO-LR4]

So the other day let the fuel get real low to where it was showing 5miles remaining. Filled it up with about 2-3 gallons. Gauge never moved after driving and multiple restarts. Filled it up later that day and I was showing approx 25-30 miles short (range to empty) of normal. That was about a week ago and same deal. Anyone ever experience this?

Short of dropping the tank and investigating and thoughts?

 

[scapistron]

Easy to lose 20-30 miles of estimated range by having a heavy foot and getting even worse mileage than normal.

 

[Rover Range]

The fuel tank is roughly four feet long.
Two gallons is not going to raise the fuel level that much.