It's the 2.0 petrol. The gauge still works I just had a look under the bonnet and it was above the max so I just took some out to the max line. It's comes and goes I just have the basic code reader so won't go into much detail.
If it's a CF3 (plastic rocker cover, two precats in the exhaust) the sensor screws into the thermostat housing. To the right of the engine as you look at it; follow the hose back from the top of the radiator to the thermostat housing.
I think there must the electrical fairies at work my petrol gauge keeps flicking empty and back to where it was all the time. The diagnostic machine don't pick this up is it worth getting on Laptop to find out properly what's going on as I'm no sparky or mechy
It could be a dodgy earth. Do any of the other guages play up as well? I wouldn't know where to start looking for the earths for the guages though. And it's about an hour's work to get the centre dash out to even change a bulb!
Another thought - how good is your battery. I've seen threads suggesting that a dying battery, while still good enough to start and run the car, can cause electrical gremlins.