P0301 and P0304 are missfires in cylinder 1 and 4 respectively. P0300 is a random missfire code. I would defenitely switch the 2 coils around and see if the missfires move to cylinders 2 and 3. If not, I would try something as simple as a good fuel injection cleaner. I have heard good thins about Chevron with Techron.
Mike