Im afraid the days of hit and miss and guesswork are long gone. Throwing parts at cars and achieving nothing is an undesirable exercise. If the miss you refer to is indeed an electrical miss, then this would be easy to locate. But not by guesswork. A scan tool hook up to this car would tell all. It would identify the actual cylinder/s that's causing the miss and, it would identify how many times it's dropping out. Example, I can hook up a scan tool, have someone drive the car until it misfires, and actually see, in real time, what cylinder is dropping out in the "mis fire" counter data of the scan tool. But this is not something you could do in your backyard. And then there's other areas of investigation. Such as a cylinder/s running lean. Lean mixtures will cause misfires under load because there is not enough fuel to attract the spark event in the combustion chamber. If all else has been tried, then Specialised equipment and know how is the modern day approach. Sorry I can't offer more. Chris
