Re: 15,000 miles and spark plug carbon closed gap??!!
Is the car burning any oil?
If so it could be a ring problem or a valve stem leak.
Also a burnt valve is a possibility.
A pressure test on that cylinder should be done and compared to the others.
Fuel problems show up as grayish or tan colored deposits, likely in the form of whiskers. They would also be on all plugs.
Last edited by onehundred80; Jul 21, 2011 at 11:17 AM.