I only had one cylinder showing a misfire as well. I would also get other codes that popped up including the MAF sensor. I am not an official mechanic and it sounds like the same issue could be caused by many different factors. Mine only happened under load. All the misfires made my Cats go out so I would refrain from driving much until it's figured out. I tried the crankshaft position sensor as well, but it did not help in my case. New Fuel Injectors have been on since Jan. and no problems whatsoever.