Fuel gauge / range meter

U lost prime in fuel delivery. Once it happns it takes long time to normalize. Car is 15yr n needs inspection of the system. Bring to independent shop that has xperience. Search surecritic.com

Sending unit is bad its float thats in the tank reads to the gauge very rare that it will be the cluster its self could even be a ground in some cases

Bad sending unit, bad ground, bad gauge, I have seen sending unit go bad they will work part way.

Fuel gauges are not meant to be precision instruments. You might want to fill up a 2 gallon can and drive the car until it runs out of fuel to see how low the gauge will go before it's really empty. Use the 2 gallons to get back to a filling station.
I once spent three working days trying to get a 1972 Chrysler to read full when it's full, half when it's half and quarter tank when the tank has a quarter amount of fuel. The customer did not want to accept anything else, but in the end all I did was to get close, not exact.
It is possible that the fuel float in the gas tank is "drowned", that is, the plastic float might have a slow leak and some fuel found its way inside. This will cause the float to submerge slightly and give you a low reading. To check this you will have to remove the float unit from the tank.
In any case, if you feel up the job (not easy) remove the float unit from the tank and manually move it up and down while checking the meter reading. You can bend the wire holding the float to correct misreadings.
Personally, I wouldn't bother, just be aware that when the reading is low, feel safe that you still have enough fuel to get to the next filling station.

Turn the ignition on and off several times before inspecting the gas tank because a blown fuse is the usual cause for fuel gauge malfunctioning. If the gauge remains motionless, check your fuse box and determine the fuse's location using your service manual.
Replace the fuse if the link is broken or damaged. Then, inspect the gauge's wire connections for cleanliness and make sure the wires are connected.
Turn the ignition switch to the "off" position. Attach one end of a jumper cable to the fuel-gauge terminal behind the gauge itself. Attach the other end to the ignition terminal.
Replace the sender unit in the gas tank if the gauge reads full and your car does not have a full tank. Replace the fuel gauge if the needle remains inoperative.

might be your gauge , have you check the resistance on it at Full 1/2 and empty and see where your tank volume is at??

also might be your instrument cluster

11.1 x 6.25 = 69.375 Litres

The sending unit in your tank is going bad replace it.

My dealer told me that if you fill up beyond the first "click" of the gas pump it will mess up the sensor in the gas tank. It might fix it's self eventually, but can be avoided if you anly fill the tank up to that "click".