Bosch acknowledges a problem with using their Bosch Platinum spark plugs
in engines with ignition systems that employ 1 coil for each pair of spark
plugs (also known as a "waste spark ignition system").

The problem that Bosch has acknowledged when using their Platinum plugs
in engines with waste spark ignition systems stems from the tendency of
electrode metal to get transferred depending upon the polarity (direction
of current flow) of the spark. In waste spark ignition systems, 1/2 of the
plugs always see reverse polarity sparks. Given the very narrow platinum
center electrode of the Bosch Platinums, performance will be degraded more
significantly when reverse polarity sparks will cause material to be
transferred from the large ground/outer electrode onto the narrow platinum
center electrode'* exposed end surface.





All GM 3800'* are Waste Spark. This is not a myth. This is from Bosch themselves, and the information was obtained the same way I obtained my information above from NGK. A phone call.

http://www.brickboard.com/ARCHIVES/1...10003481.shtml

And it'* not just them or us:

Quote:
http://www.taurusclub.com/forum/inde...showtopic=2915

AT LEAST a 36.25% failure rate in our sample size of 80 vehicles

17.5% failed immediately

Another 18.75% that didn't fail immediately failed within 20K miles (premature for a platinum plug)

There are still another 31.25% that are working so far, but haven't accumulated 20K miles yet. So they are "up for grabs" statistically, an could inflate that 36.25% failure rate even higher.

Still want to gamble?

Dan



And there'* more information out there.