rpm surging and temperature gauge that is dropping?

Go here for the surging

Refer to this link:https://www.2carpros.com/articles/engine-surges

Just to add to this one you need a new coolant temp sensor also inspect the inside of the coolant temp sensor connector if the terminals are green or blue instead of silver you will have to replace the connector as well.I have replaced a ton of those sensors for that issue and a lot of other issues.Its a really common issue on those cars.