Rough idle and loss of power

We don't have a manual on this engine so I can't provide specifics, but we need to find out if these issues in these guides are there because they will cause these issues.

First is a vacuum leak. We need to use this guide to inspect for a vacuum leak to find out if we have a line off or even an intake manifold leak:

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

Next, we need to find out if you have good compression as you will have low power and rough running if the compression is not correct.

Here is a guide that will help with this:

https://www.2carpros.com/articles/how-to-test-engine-compression

Lastly if both of these check out then we need to run through this guide that talks about this issue in more general terms:

https://www.2carpros.com/articles/symptoms-of-low-engine-power

Let's start with all this info and we can go from there. Thanks