Hi guys 

 

A while ago I had a fault with my cluster as most octys do and replaced them with a used set of clocks from eBay and thankfully all has been well until last week

I was sat at my kids school engine running and all of a sudden I heard a ping from the dash I looked down and saw the fuel gauge drop like a rocket to empty  sit there for a few seconds then go back to its original place (half)

I turned it off and back on and it's not done it since until last night I was sat in car and ping gauge dropped then straight back up 

Any ideas would be greatfully received 

Thanks

Faulty sender unit. I had strange gauge readings while under warranty, sender replaced & all was fine.

I would mostly agree. It is either the sender, panel or wiring between them.