i just recently got ngk iridium ix plugs and i noticed when i took one of my old ones out it looked pretty funny. on the ceramic insulator above the threads was burnt, or looks as if it was burnt. i was just curios if that was common or if there's something wrong.

 

How many miles on it?

 

42,256

 

how's the iridiums now? ill tune up my car tom and bought those ngks too

 

The reason why your spark plugs are burnt like this is either a spark plug failure, or too strong spark. I had that problem. My car was misfiring because 2nd spark plug (from the left) was always getting burnt.

 

i don't have them in yet, i have to pick up another spark plug socket.