iv had a problem with the truck smoking, bluish white smoke outa the tailpipe. it only really happens at idle, and smells rich, i know its unburnt fuel but why? now this only happens at or above around 4,000ft. this last weekend i noticed a knock coming from the engine, also at idle, this is the first time iv noticed the knock, and the questions from others in my camp really have me wondering. i run the juice on 0 when im in the mountians, i didn't unplug it compleatly but doesnt seem to make a difference if its set on 5 or 0. im also running PS diesel clean in the tank. any ideas?

Possibly injectors? Seems to be a standard answer. Check your oil for a diesel smell.

I was experiencing the same problem as you. I had two bad injectors replaced. Dropped off the truck Last Thursday, picked it up yesterday morning. Truck runs great, no knocks, smoke or pinging anymore. It would be a good idea to go see you dealer to get it fixed before it gets worse. Luckily my injectors weren't dumping fuel into the crankcase at the time of replacement...