On Sat, 22 Aug 2015 16:44:57 +0100, Jimbo /p wrote:

well it buggered up my '98 merc fual senders over the last ten
years.......

Did you have a test sample of identical cars, some run on supermarket,
some run on branded, large enough to rule out an individual component
failure?

No, thought not.

Ok how come it started working again with expensive 99 shell/bp ? ...

chuckle I'd love to hear the logic of how this could possibly be...

You do know how a fuel sender works, yes? It's a simple float attached to
a variable resistor.