It has been around 20 to 40 deg here and on start up my truck will run really ruff and blows white smoke then after a few seconds runs fine. Has not ever done this before even in a lot colder temps and does not do it every time does not matter if truck is cold or has been ran and is warm. when it stops truck runs great any help would be great thanks

 

Could be a sign of an injector on it's way out.

 

White smoke is incompletely burnt diesel.

Speedy may be right...you may have an injector going out.

How many miles on the truck?

How many miles on the air filter? If you have >10k on the air filter or the filter minder is deep in the yellow or red, I would change it.

How is the oil level? Is it climbing? If so, that's a sure sign an injector has failed. GET THE INJECTOR REPLACED IMMEDIATELY, before you start losing bearings.

Tony

 

Mine did exactly that before 10k miles and it was an injector, now fine.

 

I got 52000 on the truck and the air filter is a afe stage 2 the truck has not done it today at all and runs great at idle and full throttle

 

Could also be a failing or failed grid heater. The one time I skipped the grid heater I experiance the same thing at 25*.

 

Mine did it after sitting a couple days. If used regularly may not do it. Fuel leaks into cylinder while it sits a while.

 

Could also be grid heater as stated above. Luckily even when I forget to wait mine starts right up even in teens but may be colder where you are.

 

Almost forgot, my grid heater was working. Also noticed when warm driving in dark on highway if throttle up to pass could see smoke haze in mirror with headlights behind me. New injector fixed both problems in my case.

 

Thank you if it continues hope it don't but if it does all look in to it more if anyone has more input that would be great but thanks for all the help so far

 

Find a scanner and see if the IAT's rise when you start it, that will tell you if the grid heater is working or not. The temps should go from outsideish temp to 80-100*F pretty quickly.

 

Another good one for the grid heaters is to cycle them a few times when cold then look at their outside temp with an inferred thermometer. Mine went from 18 to 85.