Ah, just as I suspected...the Denso plugs (FXE24HR11) are too cold that come stock according to NGK.
Look @ teh black carbon on your plug tips to verify! NGK recommends a 7 heat range. I use NGK LZKAR7A (6799) nickels. You must change the nickels out every 30k miles or sooner, which is fine because you don't want to risk the Iridiums gaulding into your AL head at 90k+ miles.