Guys, I have fixed this problem with my XJSC. In my case, the float was partially filled with fuel and therefore reading low. If you take out the sender unit and unclip the float give it shake and it you hear fluid there your problem. I had this problem with a Mini Moke a long time ago and believe it or not the XJSC plastic float is the same as a mini. I thought it looked similar when I took it out of the jag. Ordered a new one from ebay, inexpensive, and very quick fix. Hope yours is that simple. Regards