Nissan Repair: spark plugs, vacuum leaks, rich mixture

Question
i have a 1997 nissan gxe with 130,000 miles. the spark plugs have alot of black soot after 500 miles.

Answer
Hi Albert -

Black residue means a rich mixture (too much fuel in the air to fuel ratio). Do you have any engine codes showing? Could be O2 sensor.

Do you have any driveability problems? Running rough or missing?

Also check for vacuum leaks.

Anyway, could you get back to me, the more info you can give me, the better I can assist with the diagnosis.

Hope this helps -
aloha
calvin