I recently changed all my NGK spark plugs a few days ago, and upon looking at the color of them, they were all of a cherry-reddish color. I looked in the Haynes manual but I don't see this type of coloration. I had about 55,000 miles on these plugs before I changed them, but I have no idea what had caused this type of coloration. What does this mean? I never had any starting problems before, except when I had to replaced the front left-bank O2 sensor. Is it my fuel ratio? I always run 92 octane in my car since the day I bought it, like 7 years ago. Anybody with any thoughts about this?

 

Looks like your plugs were MMT fouled. In other words, your engine is A-OK. Look here;

http://www.fiatparts.com/colorplg.htm

DW

 

Thanks, dwapenyi. I was confused on this because when the plugs were first changed at 60,000 they were normal in color, according to the Haynes manual. I did not want to pull one of the new plugs out just to see if there were any changes in coloration. After that knock sensor install, I dont't feel like going under my hood. That manifold scratched up my hands!