Fuel gauge shows empty petrol tank.But really it is full. Where is the problem?
does it i have a digital display or is it a Variable resistor, it really common for it to happen on the Variable resistor types gauges because it will have scratched the soft metal make the gauge not Register the reading, i wouldn't have a clue as to how much to replace but i would also look at the sender unit in the fuel pump to make sure it moves up and down. i hope this helps.
Mathew is on the right track, but there's also the old float system. if the float is jammed or stuck in the down position (which isn't uncommon if you've ran the car out of gas prior to this happening. That little tiny float type device is connected electronically to the fuel level indicator relay which is what receives the signal from the tank and adjusts the analogue or digital display on your dash.
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