i recently installed a set of denso iridium iw24 in my 635 turbo('87 carteck system). problem is upon cold start up the plug tend to gas foul sometime they start to fire after warm up but sometime they need to be removed and cleaned.i'm sure i've gone with to cold of a plug...any suggestions on a heat that would cure this.buy the way i have a great spark from msd ign.. thanks kevin