Just the other day out of nowhere when I started my 05' (60,00 miles)it idled rough for about 2-3 seconds and blew a fair amount of white smoke. Temp was around 45 outside. Has never done this before even in much colder weather. Has done this several times now. Runs perfect after the first 2-3 seconds. Did it the other day after sitting just three hours in mid 50's temps.
Just drained water/fuel seperator the other day and Fleetguard filter has about 6000 miles on it.
Any ideas? My own idea leads towards bad injector or heating grid going out.

Thanks,

Bill

05', 4x4, G56, QCLB

 

A sign of a sticky/leaky injector. . . .start with a good bottle of injector cleaner in your fuel. . . .then see what you get. . . .

Others have said you might need to run it pretty hard being a med duty engine to keep those injectors nice and clean.

 

There is a tsb flash for that. I had the same problem and it took two injectors to fix it. So it could be either or.

 

I had the same problem.Upgraded to F1 injectors and still had it.Problem went away with newest Smarty download.I guess because smarty has newest DC flash files.