Not sure I'm going to change it now... But there were a couple times that the temp. went up in my car. Thought that maybe the thermostat was bad but now I don't know. It seems to be doing ok right now.

 

Ok, I see. The computer will throw a code if the sensor goes bad. The code will be specifically for the sensor. There is another code for the thermostat: P0128 code - Coolant Temperature Below Thermostat Regulating Temperature. These seem to be pretty accurate codes in diagnosing issues. If you are not getting a code then look for things like low coolant levels and front mounted radiator fans. Leaves and bugs can block radiator airflow and cause higher temps too.