Fuel gauge problem

[SimonR.]

I thought it was acting funny but now I know that I have not used half a tank of petrol doing 50 miles.

Not driving hard at all, changing gear normally etc

Any ideas?

 

[MicKPM]

Sure you've not got a leak?

 

[SimonR.]

Don't think so because when I start it up again it says nearly full. Then back down, then up etc. It's so random