I have a steady check engine light on giving code P0302 as a reason.

What is your question?

I had a tune up done at Dodge dealer. I regularly clean the fuel system and replace filters. The vehicle runs great at speed and at idle. If I detect anything it is a possible very subtle brief stumble at idle, but I'm not even sure I feel that and it definitely does not always occur. I am not sure if I should even drive the vehicle until I can get repairs done.

What makes this problem better or worse?

Nothing