another temp gauge/fuel gauge/voltage regulator thread
I would get a aftermarket temp gauge so you know where you are really at. You can buy a mechanical one that installs in the upper radiator hose pretty easily.
Depending on how bad you want the oem one, this can be a good solution.
Some folks don’t like the radiator hose senders because they won’t read if there is no water flow. However, I like them because I can see exactly when the thermostat opens. As long as you keep in mind the limitations and keep your radiator full, they are a cheap easy solution to a bad oem gauge.