S1 Stack Readings (Fuel Level)

[Rus]

Soooooo, something a little strange happening to the fuel level readings on my S1. When the engine is running all seems fine, until I increase the revs to a constant 2k ish. At this point the fuel level reading slowly changes (increases).

 

I've searched but haven't found anyone with this problem before (temp readings seem to be behaving normally).

 

I've cleaned the earth points on the chassis at the battery, engine/gearbox & earth stud next to the ecu. Is there an earth near the stack unit under the dash? Or something on the fuel tank?

 

Battery is pretty old, 9 years at least, but seems to be fine.

 

Open to suggestions....!

 

Russ