I have an AU3 Falcon Sedan on factory LPG, and I have noticed recently that the fuel gauge will not go below three quarter fill when using the car. I use the trip meter as a guide as to how much fuel I have left in the tanks, but I would like to have the gauge working as well.

Would be a faulty gauge/dash cluster (easy fix), or would it be a faulty sender? If it is a faulty send in the tank, what sort of dollars would I be looking at to get it fixed?

Any help would be greatly appreciated.