Has anyone replace this sensor? The wifes temp gauge read overheating but when I check the temp with a thermometer it reads within operational limits. It also will shoot up seconds after starting the car or not at all. I have already replaced the thermostat with no luck. So I figure thats my next step.
Thanks.

 

It sounds to me like the sensor is toast but here is a quick and easy test if you have some sort of multimeter or resistance meter.
Let the car sit overnight, then disconnect the wiring from the temp sensor. Set your multimeter to 20k for resistance and record or just remember the reading.
Next start the car and let it idle for 2 minutes and then shut it off.
Now check the reading again using the same 20k setting. The resistance should change by around 200 or so if the sensor is good. If not its toast

If you dont have a way to test it just change it its pretty inexpensive and easy to change just drain some coolant out first and get a deep well socket on it.