MoTox8410 Posted February 14, 2005 Report Share Posted February 14, 2005 Like others have said, this is due to the waste-spark ignition. Waste spark ignition fires 3 plugs with normal polarity, the other 3 plugs fire with a reverse polarity. That reverse polarity eats the platinum center electrode like candy. Bosch plugs are fine and great in a distributor or coil-on-plug ignition system, but I wouldn't use them on a waste spark ignition unless you like replacing them often (or at least replacing 3 of them often!). which are the 3 fired with reverse polarity on the 3.4 DOHC Quote Link to comment Share on other sites More sharing options...
Brian P Posted February 14, 2005 Report Share Posted February 14, 2005 they're all going to see the "waste spark" during the exhaust stroke. BOSCH's suck to high heaven on a GM and most domestic ignition systems. You'll get MAYBE 10k before they foul up. I don't even recommend them for imports. At my job, when I write up work orders for tuneups, I will pick anything other than BOSCH. Be it Delco, Autolite, NGK, etc Quote Link to comment Share on other sites More sharing options...
GPRACER Posted February 15, 2005 Report Share Posted February 15, 2005 BOSH works well in my lawnmower, other then that they suck. GM engines were designed with AC Delco plugs, why would you use anything else? They are cheap and they work. Quote Link to comment Share on other sites More sharing options...
GnatGoSplat Posted February 15, 2005 Report Share Posted February 15, 2005 They're all going to see the waste spark, but only 3 fire in reverse polarity with reference to ground. I don't know which 3 those would be though. It depends on how the coil is wound. Quote Link to comment Share on other sites More sharing options...
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