When the engine reaches operating temperature, the gauge starts to malfunction and the engine loses power

Hi,

It could be the sensor or wiring that is shorting. Have you inspected the sensor connector and wiring?

Also, have you had the computer scanned for diagnostic trouble codes? That can point us in the right direction as well. Most parts stores will do it free of charge.

If that appears good, for the price, I would replace it. Here is a link that explains how in general it is done:

https://www.2carpros.com/articles/coolant-temperature-sensor-cts-replacement

If you do have the computer scanned, let me know what codes are retrieved.

I will watch for your reply.

Take care,

Joe