03' C-15 miss at startup

my engine sometimes when I 1st crank it seems to have a miss (hard miss...truck shaking) it usually only lasts
a few seconds and smooths out....when it does this it white smokes a bit and you can smell oil burning....it may do
it 4 or 5 times in a row and then it may go a month without doing it.....

people have told me injector, but that does'nt explain oil burning smell to me.....when it doesnt have the miss
at startup it doesnt white smoke or have the smell

it almost has a soft popping out of the exhaust....not loud but thats the only way i know to describe it

 

my truck started doing this before the engine went down because of a gaulded piston.....when i had rebuild
done i had 6 new injectors put in.....i wouldnt think but i know new parts fail also that its an injector....i wonder if maybe
it could be a wire that goes to the injector not getting good connection or the harness or something....not good
connection makes since to me because it does from time to time like a loose wire but would think when they
were installed all connetions would've been made good

 

if its an injector wouldnt it keep missing or cause the truck to run bad?