Originally Posted by hardhatz
the reason I think it is getting air is that it misses, bucks, and snorts on startup after several hours of being parked some after 8 hours of sitting, a lot more after 24 hours. First happened about a month ago, up in Washington. I thought it was from the -20 temp during the night, but since that day it has done it every day. It smoothes out after a minute or two.
In addition, it died yesterday on the freeway & won't start at all. Dunno if related or not, but either way I want to fix both issues.
Sounds like the classic 6.0L injector stiction issue, which can only be diagnosed using the power balance screen to check, when it misses and runs rough. Another quick and easy test you can try yourself, is to remove the secondary fuel filter and fill up the housing. Crank the engine over with the key out of the ignition, by using the jump starter on the passenger side of the engine, and peak inside the secondary fuel filter housing for the presence of bubble(s). If bubbles appear, it means you have compression gases leaking into the fuel system.