Spark plugs are black?

I would replace the spark plugs because when they are fouled the engine will not run correctly. Also, I would check the fuel pressure regulator which can leak and cause the problem you are having.

This guide can help as well:

https://www.2carpros.com/articles/comprehensive-guide-to-diagnosing-and-resolving-rich-running-issues-in-your-automobile

Remove the vacuum line from the regulator, there should not be gas present. Check out the images (below). Let us know what happens and please upload pictures or videos of the problem so we can see what's going on.