Thank you all very much.
Someone mentions bad gas. I only use Shell, BP, or Mobile. So bad gas can't really be the issue. Unless bad batch of gas. But in the end I figured out what caused that specific code to pop up.
When I was turning the key to do the test I turned it a little to far to the point of turning in the engine and then turned it off. So the engine started turning over but turned it off immediately before the engine could start throwing the P0300 code. As for the CEL being on right now. And before that. I don't know. After doing the test 3 times I'm not getting any codes popping up. So I'll be calling my dealer today to set up an appointment to go in Saturday morning for them to check it out and see what is causing it and having them delete it. My salesman thinks it might be a faulty sensor or a sensor misread something throwing the CEL.