2000 Citroen Xsara Picasso fuel gauge fault

It may not be much help but I had the same thing when I first got mine secondhand in January. I thought it might be because it had been standing on the used car lot for a while. After parking on a steep car park and reversing up and down into a space to get the feel of this new car (after a volvo estate) surprise surprise the guage worked! Maybe a float mechanism stuck? Its done it once or twice since after filling up with petrol, but worked the next day. I've just ordered a workshop manual via amazon to see what the mechanism is (plus a few other niggly faults).

I too have similar problems with my fuel gauge it stays on the red or orange light when i put £10 fuel in sometimes more then i think its empty put in £6 and end up with four or five bars! thank you your information could be useful.

Thanks Edders. Mine seems to have settled down a bit but I'm still not convinced its showing an accurate reading. I get used to keeping my fuel receipt, trying to get the same amount each time (eg 20 litres), then guesstimating that I can do say a hundred miles on it round town (err on the safe side), then set the trip meter to zero as soon as the petrol has gone in. It makes me feel a bit safer about running out unexpectedly. (NB I had a volvo before with a completely defunct guage, so I was well used to this system. It never let me down even touring in Europe - but ironically it was one of the reasons I traded in for this Citroen). I found the workshop manual little help, only to convince me there was nothing I could do myself, and I am reluctant to go to a dealer for fear of the kind of massive bill if they insist on taking out the fuel tank or worse!.