I have read through countless misfire threads however none have mentioned any kind of carbon build up causing problems. I spoke with an extremely knowledgeable mechanic friend yesterday and after listening to the small puffs/misfires at idle in my car, he explained that it was simply excess carbon that basically ignites and creates in essence a "second spark" at random intervals. This would explain why the misfires ONLY occur at idle after driving for a while and will fade away and disappear after the car idles a few minutes. Basically I was told this excess carbon build up glows red while driving and somewhat cools and goes out after idling a while, which is why the misfires stop. It was lastly explained that this situation is more likely to happen in a car that consumes some oil like the s2000.

I am curious to hear what others think of this theory as I have not previously heard or read about this situation...at least in modern cars. Either way he advised me to run some kind of carbon cleaner through the system to clean this build up on the head and possibly the top of the pistons. Everyone on this site seems to talk about the injectors being the culprit and adding an injector cleaner in the gas. Is this the same stuff as this so called carbon cleaner? What do you guys think?

To give some quick info on my situation I have NO check engine lights and have so far replaced spark plugs, done the map ziptie fix and tested compression that came up perfect. The spark plugs are gapped correctly and everything is at the torque to spec. I was about to order all new injectors before I heard this but I think I will hold off now.

 

I'm misfiring with only 10K on the car. I just posted under this section.

 

Did your car throw a code?

 

so interesting it had to be posted on multiple sites? lol