After the last 2 fills, I noticed my fuel gauge was not indicating completely full. It would vary between 7/8 and 3/4 while driving. When stopped, the gauge goes to full, but as soon as one drives away it then goes back down.

A possibility is that the float in the sender has absorbed fuel and is now just barely buoyant so when stopped it floats to the top, but the bumps and shakes cause it to partially submerge while driving. Can anyone report what the float is made of, is it hollow and has there been any history of the floats losing their buoyancy?

I suppose there are many other possibilities from the sender's potentiometer, the wiring and contacts to the gauge itself.

But it seems every problem I experience has been solved by someone else here already and that saves a lot of effort!

Andy

 

Mine fluctuates slightly as well (tho not sure if as dramatically as yours). When I first noticed it I thought to myself, wow, this car eats fuel, but then it would bounce back up again.

I have no idea what causes it, but in the grand scheme of things, it's a very minor quirk.

 

This how you can check your fuel sending unit for your 1998. It is not the same for a 2005.

Link JagRepair.com - Jaguar Repair Information Resource

 

Thanks Gus.

That is a great explanation of changing the float/sender.

Andy