I've got an '05 2500HD with the 6.0L vortec, and the check engine light is on in the dash. I scanned it at a local Advance Auto and it said "Knock Sensor Bank 1 - Random Misfire", but it doesn't say which cylinder.
So, is it a misfire, or is the knock sensor bad? I've put brand new ngk plugs and AC Delco wires on it less than 2 months ago, and i'm really hoping I don't have to replace any coil packs(since there's one for every cylinder and they're $50 bucks a piece).

 

Take off your intake manifold and remove your knock sensors. Clean them and put some of that black gasket seal under the grommet when you install. Factory set up let's water and crud get down in those knock sensors. Reset the truck and boom.