Hoping my sender unit is going to be ok for the aux tank!

Being testing it for half an hour now, it definitely reads resistance when moving the float but It's not steady, jumps around and sometimes goes back to the original reading from when float is at bottom although float is at top.

All connections seem fine and is clean on the sender slider reading thinngy, not bent and actually looks in pretty good condition but it worries me.

Not sure what to do as it does read changes in float movement....Bugger!!!!