Mine sticks on zero when the level is low and I park on my sons drive which is about a 30 degree slope.
When I drive over a bump, the needle bounces back into life. It is OK when the tank is full.
None of this is much help to you. It was a cheap level gauge from Island4x4.
2000 Range Rover 2.5 DSE HP24 auto, uprated torque converter - JFearn chip, larger intercooler, removable winch, stainless exhaust, alloy radiator, Gen III's, Terrafirma +2" shocks, GG AT2/3's.
Full Fat Faultmate able to do all models.
- ex 1996 Discovery 2.5 300Tdi diesel auto
- ex-1982 Classic 3.86 Perkins diesel manual