The parts you replaced are involved in producing the spark. You have spark so why would you replace those parts? If the engine is running, you know spark is getting to the spark plugs, at least most of the time. If that spark is occurring at a different location, there is either a carbon track or some other reason the spark is not jumping the spark plug gap. The spark is always going to occur at the point of least resistance. A carbon track is a perfect example. Most of the time that can not be cleaned sufficiently to prevent the problem from coming back.
While a carbon track makes it easier for the spark to occur at the wrong place, the same thing can happen when it's harder to jump at the right place. Look for a carbon-impregnated string in the spark plug burned away from the terminal. That is the single biggest reason for a misfire, and new wires will take care of that. That makes it hard for the spark to get to the plug so it looks for an easier way to get back to ground.
Thursday, December 29th, 2011 AT 2:19 AM