F355 misfiring badly

Had an engine misfire problem recently, i checked everything from spark plugs, 02 sensors, air leaks etc. I couldnt find the problem myself , so i took it to the ferrari dealer here in Melbourne and they found one of the HT leads faulty. These HT leads were only a few years old (after market type). So i replaced all with factory leads. My recommendation is check every HT wire resistance and make sure they are good.