I have a 2001 Ford Taurus that intermittenly displays an abnormal high temp reading on my guage. The car has a new water pump, new thermostat and no visible leaks from the radiator. Coolant is at the proper level. The temp guage goes 3/4 the way up to the hot level and then goes back down when I am running at highway speeds. The fluctuating temp occurs when I am sitting at a traffic light for a period of time.