Nissan Repair: spark plug burnout!!, nissan hardbody, sparkplug

Question
I have a 1995 Nissan Hardbody XE (V6) pickup with about
200,000 on it.  The dummy engine light is coming on and
off now, and in an attempt to figure it out, I found a burned
out spark plug.  I replaced it, and only two others that I
could get to, only to find it burned out again the next day,
with the same engine light and such.  I cannot find a good
Nissan mechanic 'round here, and wondered if you had any
input?  I have considered water in the gas, or maybe one of
the three plugs, that I cannot reach, is also burned, and
burning others?  Thanks so much for any help you can
offer.....
joe

Answer
Joe,

Are you saying that the ends of the sparkplug are burnt off?  If this is the case you are running way too lean and burning the electrode off.  Check the fuel pressure and make sure that you are putting out enough from the alternator to run the injectors properly.  I once had a car that had a bad alternator and it ran so hot that the exhaust manifolds glowed  orange.  It was the alternator and it required a new set of plugs.  Now, if the cylinders are carboned up the extra compression or knocking could cause what you describe.  That is, if the electrode is being busted off from knocking.