Reduced power message and the engine misfires?

This can happen when the spark plugs are worn out. I would start with plugs and coils which are common.

Here is a generic guide to help with instructions in the images below for your car:

https://www.2carpros.com/articles/how-to-change-spark-plugs

and

https://www.2carpros.com/articles/throttle-actuator-service

Also, I would service the throttle body. Check out the images (below). Let us know what happens and please upload pictures or videos of the problem.