spark plugs condition

For some time now I have heard that you can assess your engine combustion
condition by carefully exams your engine spark plugs after a long highway
trip or verify exhaust tail pipe for light tan color. I drove over 1400 km
last week (all highway) and my exhaust tail pipe is totally black. I
decided to check the spark plugs condition specifically the color of the
electrode. All spark plugs have light tan in color from the center of
the electrode to the top of the ground pin. I don't understand why my
exhaust tail pipe is black ? The car is running fine. I lost a bit of
engine oil but I think I have minor leak somewhere along the valve cover
seal since my spark plug is clean.

Any ideas?

 

Mine has always been black - very black - on both of my Saturns. And my
newest one I've had for 11 years.

Why do you feel that black is an indicator of something wrong?

Lane [ l a n e @ p a i r . c o m ]

 

Perhaps there is nothing wrong with my car, but my wife's and my brother
cars both have clean exhaust. I have started to monitor other cars and most
of them are clean. So I am just wondering.