Greetings. My XJS fuel gauge / fuel level sending unit is acting erratic. After I fill up to a full tank, the gauge will rest at about 80% full. The gauge will quickly go down to 25 to 40% full after a few days of short driving. Then, if I go downhill (i.e. into a deep circular underground carpark) the empty warning light comes on. Once I reach level ground at the bottom of a car park, the gauge goes back up to 25 to 40% full. When I go to fill up, the car is usually more than half full.

Is this likely a problem with fuel level sending unit?

Many thanks,
Charles

 

Charles,

On facelift cars, it's as, if not more, likely to be an issue with the anti-slosh module. Over time, they start to "leak" current and the gauge drops quickly. Try bypassing it and see if the gauge returns to a steady state. If you don't know how to do that, post back and I'll explain.

Paul

 

Thank you Paul!
Will try that. I am sure it hasn't been replaced since it was new.
Best wishes,
Charles