I have a 97 Ford F150 and I've been having problems with the engine overheating, or so I thought. Every time I drive the temperature gauge just shoots up to the hottest it will go; most of the time it's just when I'm slowing down or completely stopped. I've taken it to get the radiator flushed, I've changed out the thermometer, I've changed out the sensor multiple times and even had the sensor unplugged and the gauge keeps flying up. The engine doesn't smoke or anything but it runs like its overheating and gets all shaky so I have to pull over, turn off the engine, wait a few seconds, and turn it back on.

Sometimes when I'm on the highway the gauge will fly up like it does and then just goes back down to normal; but then again sometimes it flies up and stays up. So I have no clue what's going on.

If anyone can help me out, please let me know.

Low on coolant. Bad thermostat. Radiator fan not coming on. Those are the items that come to the top of the list.

You may need to replace the radiator, due to phosphate scale. This link may help:

https://www.askmehelpdesk.com/cars-trucks/faq-how-troubleshoot-repair-maintain-hondas-selected-other-vehicles-46563-3.html#post235973