Hey everyone glad to be here. I have an 06 accent 93,000 miles. Today it was about 18 degrees Fahrenheit outside and when I started the car it immediately ran rough and misfired engine light was flashing. This only last 10 seconds or so. Then it smoothed out and engine light quit flashing. I immediately checked the code it was p0304. The car has new plugs (ngk) and ran perfect the rest of the day. Any ideas? Thanks for the help everyone!