Here’s the deal I got a 2003 6.0 with 112,000 miles on the odometer.Truck has EGR delete, studs, AFE Stage 1 cold air intake, 4” turbo back exhaust, SCT Livewire tuner

On cold start ups (weather has been in the mid twenties over night) without being plugged in the truck will lope (run rough) at idle and belch smoke for about 30-45 seconds depending on ambient temperature, during this time of loping if I push on the accelerator and bring the rpms up to 1000 it will smooth out and no smoke. Truck has never not started when cold. If I plug the truck in no loping (runs smooth) no smoking. Truck always starts up smooth when engine coolant temperatures are 70 degrees or above.
Currently the truck has 15-40w oil and will be changing to 5-40w

I’ve tested the FICM and it test good in the key on engine off position and the key on engine on position both positions 47 volts. Amp checked the glow plugs and checked good.
DTC code p0401 is the only code pulled and seems to be a common code for the EGR delete?

I’ve read where there have been some that have tested the FICM and tested good yet by replacing the FICM it cured their problems, anybody else experience this?
What else should I be looking for?

 

I have a 2006 6.0L and mine has to idle for at least 15-20min before I take off down the road when the outside temp is 60 degrees or under. Otherwise it will blow white smoke and run like crap for about a mile then it clears up and runs fine. I don't know what's going on with it. I've been told the turbo needs taken off and the variable vains cleaned. My issue might be a little further along than yours but the symptoms sound very similar, mines just a little worse.