Wrong temp reading on anolog gauge

when the engine is cold on start up the gauge will jump above a 50 % reading.there is no over heating or loss of fluid.car has heat.changed temp sensor closest to the top radiator hose without a fix.can u tell me next part and location?

It’s a Grand Marquis. They stopped making the Marquis long before 1995. Anyway, try www.crownvic.net for specific help for your car and problem.