Ive noticed a couple times that if my truck idles a long time like more than 15 minutes that i get a very little amount of blue haze. The color is even a little hard to see and i have to back up 30 feet to see it after staring hard at it. Is this normal? My egts at this time get down to 280. Buddy said it could be a little unburnt fuel from idling so long. Looks like the same smoke at a cold start up. Havent lost any oil or power. No blue or white smoke when i drive.