when it runs out of petrol as mentioned is the tank bone dry?
you tried starting it again 10 minutes later?
unless someone has either had the dash out which is highly unlikely to effect the fuel read out, then your sensor in the tank is dodgy or the float arm is not sitting at the bottom of the tank correctly,
mine ran up till half a tank then it stopped, you couldnt start it straight away and was led to believe it had ran out of petrol. started up after 10 minutes.
check if there is still fuel in the car, if the pump is playing up it will cut out and lead you to believe the car is running out of fuel, the reason why it could be quarter of a tank is because there is less fuel in the tank and crap in the tank is not dispursed so much and is drawn into the fuel pump, it stops your pump and it stops the fuel you get the impression it dies. when you leave it the muck that got stuck in the pump drops to the bottom of the tank again and the pump works again and the car starts.
honestly look into the tank have a good look around for rust or plastic propellers i had 6 of em sitting in the bottom of the tank.
a garage tested my pump and said it was fine, it was only until i looked into the tank i found a right mess and the pump had only two propellers left on it.
i uploaded a photo showing the bottom of the lift pump, you can see the little opening with the propellers.
it seems silly but it took me month to figure it out having gone through every section of the car.
the variable resistor can fail and stick as mentioned before.
