Lately I have had the problem of the fuel gauge not registering when vehicle is started and driven for approx 50 kms before the gauge begins working. Then after fueling the problem starts again if I shut the engine off.

 

On those year vehicles, if you grounded the wire from the fuel tank sending unit, the gauge would go to full.
If you try that at the tank and it does that,it would confirm the sending unit in the tank is defective and will need to be replaced. If no change noticed, problem with wiring up to dash or dash unit is defective..Sending unit in tank is called fuel tank module..