There are two thermostats for this vehicle . Did you change both of them ? Also there is a sensor that sits right on top of the thermostat housing if you take that off you will see that it has a Copper leg that regulates the temp. Instead of buying a new one I just took a wire brushes to it and cleaned it up. I didn’t even know it was copper and until cleaned it. there is a small black O-ring that sits on the bottom of copper leg, i’d Replace that after cleaning it.