Damn, skipped right over the plug wires and went right to the o2 sensor? I would do plugs, wires, coils then o2sensor. Go in order of cost, lol. But yeah, you got wires and coils before heading into crapitznottheeasystuffland.........also check for cracks in the rubber accordian intake tube? Not sure that would cause misfire codes. Misfire codes usually plug/wire/coil thing.