temp reading on dash

my wifes gti temp guage keeps flashing and the needle points way over to the right,from the time you first turn it over (from cold) up untill you switch it off.

any ideas what this might be?

the temprature sender might be mullered mate, failing that my old 1600Gti used to do it, the water pump and stat were knckered mate, funny that my 1800GTi just started overheating, new water pump and stat just to be on the safe side i think.

Cheers scott