been gone a while got a couple questions
 

Ok first off its good to be back been gone a while now for tge questions on my 97 k3500 6.5 every time I start the truck I get a puff of white smoke and it surges (rpms go up and down) until it gets to operating temperature after that it runs like a dream what would cause the surge? Replaced lp new injectors and the second question is last winter I put it in 4hi went to back out of my drive and heard a pop come from the front end and 4x4 hasn't engaged since but nothing is broken ive checked the cv axles and all idk what it would cause that? Could the actuator be bad? Would that make the pop noise? Any help is appreciated

Check for trouble codes?
Air in the fuel could be causing the surge?
replace the IP fuel return hose with clear diesel rated fuel line and watch for bubbles when it's idling.
Timing problem?
Bad CPS?

Very likely that the frt axle actuator has failed-they were troublesome.

No codes had it scanned several times

X2 on the actuator they are the weak link just replaced mine,check the 4X4 fuse if blown the actuator is bad.

Thats what im hoping it is but tge only thing that has me confused is the pop I heard I ddidn't know if the actuator would make that sound