Spark Plug

[beagleboy]

Last Fall I replaced the plugs and wires on my metro. Since then I have had 1 plug go out me about once a month. It is always the same spark plug. I've cleaned the rotor, but haven't replaced it. What is the problem?

[geozukigti]

What color is the plug? Is it fouled out? or burnt up?

[beagleboy]

No, The plug is pretty clean when I pull it. It is black there is no carbon or anything.

[geozukigti]

If it's black, it's most likely running rich. You may want to upgrade the ignition coil, or replace the cap and rotor or both. Also, check and see if your ignition timing is ok.