Erratic Fuel Gauge

[darrenchadwick]

The fuel gauage in the van started playing up recently (after a fill up at a fuel station). The needle on the gauge occassionally shows the wrong fuel content of the tank. I know this because of the quantity of fuel placed in the tank from time to time. It is erratic and works fine for a few days but then occassionally the needle will say there is no fuel when I know that there is at least a quarter tank for example. If I leave the vehicle to nip into a shop for example and then come back and start up the van, the needle will sometimes work normally again. This problem varies from day to day and sometimes not for a few days. I dont think its the dash instrument as everythig else is fine (though not 100% sure) so I wondered if it might be the fuel sensor on the tank?
Any suggestions?
PS. The vehicle recently had an MOT and I had a problem with the airbag light coming on on the dahs from time to time and staying on occassionally. I dont know if the garage guys had a tinker with anything to solve this but it didnt cure it although it did pass MOT. There may be no link with the fuel gauage it could be a coincidence.

[tucker]

The fuel gauge on the berlingo is odd. It is not constantly reading the tank contents. It doesn't work like that.

It reads the tank contents periodically and only adjusts if the amount is 10 or more litres adrift. It also reads it if you refill with enough fuel. After that initial read, it calculates what is being burnt through the engine and deducts it and that's what the needles shows.. basically an estimate based on what you have used since last read.

I have discovered this because mine is LPG and the needles drops as though I am using petrol when I am not. Then when the difference is apparent it resets itself.

Hence it may not be the tank sensor that's at fault??