Erratic fuel gauge

Good day all.
Has anyone had these symptoms from the fuel gauge on a 2003 Symbol.
On turning the ignition on the fuel gauge rises to above full. With the engine running the needle
slowly falls to about 3/4 full and then equally slowly rises to above the full mark again. All the time the
engine is running it cycles through that sequence.
We went to Hunstanton last week, a round trip of about 350 miles without any problems. I have done 150 miles since the last fill up so not related to that. Hope it's no the tank sender, pricey I think.

I would first check connections at the sender and the earth connection.

Yes I will, any idea where the sender is mounted Paul?

Having never really looked, I imagine the tank must be under the front floor area, perhaps there is an access hole under the carpet.

There was a thread about fuel tank access panel in the cab area, new van but may be similar. [You must be registered and logged in to see this link.]

Can't find anything obvious. I will have to climb underneath sometime.
When we first got the van the tank leaked somewhere and the fitters removed it but they had a post lift so easier.
I had a look at the link Peter but nothing like it on a 2003 chassis. AFAICS
Bert

Hi
I think this maybe the fuel gauge voltage stabiliser fitted beside the heater box behind dash, small black box about size of a fag packet. Very easy job to change yourself ( centre of dash )
Hope that helps
John Dean

Thanks a lot John. We are off again Monday so I will see how it goes and maybe have a look at it while we are away. I've changed the radio so should remember how to get in there!

All OK again! A few miles from home the gauge started to show the correct value and when I filled up that was OK. 190 miles later it's still right. Going to top up again in Great Yarmouth,see what happens then.
Must have been the higher voltage kicked it back into life!
Bert