RPM's keep jumping up and down/erratic?

The most common cause of this is a vacuum leak. Here is a guide that will help with this:

https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge

Also, here is a guide that will help with surging issues:

https://www.2carpros.com/articles/engine-surges

Basically we need to run through this and determine what the cause is. Clearly it could be a couple things but the most common are intake manifold leaks or hose leaks.

So here is a video that will help as well. It covers the same basic info but some people just prefer videos.

https://www.youtube.com/watch?v=xN5pcM-5bso

Let us know if you have other questions. Thanks