Somehow the spark plug managed to work its way all the way out of the head. This is an Evo 9 too with the extra reach spark plugs. The knocking noise was combustion not being kept in the cylinder and exiting past the spark plug to the area below the plug cover. This caused the spark plug to jump up and down repeatedly mauling the top threads on the spark plug hole. Combustion getting past the spark plug ended up melting the spark plug wire and melted the coil plug to the coil.

I was able to clean up the threads of the spark plug hole with a tap and saved an expensive head R&R. A new set of plugs and wires and a little clean up of the wiring and it will be all good.

 

Funny same thing was happening to my friend about 2 weeks ago, His spark plug was getting smashed everytime he got into boost his spark plug in cyl 4 was fouling. A piece of the piston had cracked and that piece kept smacking his plug closing the gap and fouling the plug, needless to say I hope this isn't the same case for you but just throwing that out there. Goodluck!

 

Thank you for the update Ivan, I'm sure this will help a lot of people with similar problems out in the future.

 

hell yeah!! wow man thank you so much...i was expecting the worst! you saved me

 

also were you able to, or are you going to do a boost leak check or put the mass air flow adapter kit on (not sure if that is what its called)?

 

We did not have Evo 9 plug wires in stock and had to order them. They will be in Monday. I will take care of the boost leak test and put the adapter and filter on then. I did get a new spark plug in and fired the car up on a doner Evo 9 plug wire. The motor appears to be just fine.

 

WOW, thats crazy! Have you ever seen that before, on an VIII or IX?

 

even after certain death, the beast continues on... i just got my car back from ams today, she runs perfect... got her home did a compression check on all the spark plugs and my results were wonderful between 150 - 153. Thank you Ivan!! oh and if anyones got a used AMS intercooler they want to get rid of message me i know