I have a 03 6.0 and it starting blowing white smoke while at idle. It really pours out the smoke. When at highway speeds alot less smoke but, what is coming out seems to be black. Truck still runs fine and idles fine. Check engine light is on and a shop hooked it up to computer and said it was #4 and #8 injector but, they were also a shop that has never worked on a 6.0 and rarely on diesels. I was told by a other mechanic it might not be the injectors at all and did not want to give me any ideas on what it might be with out letting him look at it first. Can anyone give me any signs to look for to point me in the right direction.