This probably will not apply to your situation but, last week I had the same problem with my wife's Mazda. Turned out to be a valve cover leak. Oil was oozing down to the spark plug, creating the missfire. Once the oil burned off, all was fine, untill it happened again. New gaskets fixed our problem.
Are you just getting the code? Or, are you actually hearing/feeling the missfire? If it's just the code your seeing, I wouldnt worry too much about it. If not, I hope these guys here can help you more than I can.
Good luck, and welcome to the forum. J-Bird