<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Steady Eddie:
Anyone ever heard this one?
Is it true?
Supposedly, if your Vortec throws a misfire
code, which is cylinder specific, say, #3
cylinder, and you find a bad spark plug, you cannot simply change that one plug, but you have to change the WHOLE set....one new spark plug will fire sooner that the other old 7 plugs
and the PCM will hear it as a "ping" and promptly retard the spark advance, costing power. </div></BLOCKQUOTE>
This may be a good question for Mike in the
I wouldn't think that a newer plug would fire appreciably sooner however if you did not match the temperature rating and put in a replacement plug that was hotter then the rest or put in the correct plug but did not gap it properly then I suppose that predetonation could result. It would also depend on how old the plugs were. If the set was near the end of its lifespan then it would only make sense to replace the whole set however if after a short time you discoverd that you installed one defective plug and needed to replace it then I wouldn't think that would be a problem.