Still sounds like it has a fouled plug?

Hello,

Typically when the engine misfires, it will produce fault code and the engine light will be illuminated.
Is the check engine light on?

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

Keep in mind that a spark plug can misfire due to a faulty coil pack. Sometimes when you have an issue with the coil pack it will produce random misfires.

Here is a helpful guide:

https://www.2carpros.com/articles/how-to-test-an-ignition-system

Also using premium gas will not trigger misfire.

I have attached diagrams for your reference.

Please let me know of any questions.
Thank you.