i have z 92 6.5 turbo 3500 if would stumble a bit when I revv it up and it idles down nod it idles rough and blows black smoke any help would b great

 

Injectors ever been changed?
IP ever been changed?
How does it start hot?

 

Injectors havent been changed starts fine hot or cold

 

Black smoke is too much fuel,could be leaking injectors or injectors that are popping off too early?
Or a dirty air filter.

 

White smoke sorry

 

Any bubbles in the rad when running?
Does the upper rad hose get hard as soon as you start a cold engine?If so then likely a blown head gasket or cracked cylinder head.

Could also be incomplete combustion if it only does it cold and be caused by non working glow plugs?

 

Does the smoke smell like fuel or does it smell sweet ?

 

I also get diesel in crank case it smokes white immediate after starting

 

Non working glow plugs in some cylinders along with pissing injectors is a good bet.

 

If you have no problems with the cooling system, you could try to adjust your IP timing. I'd venture a guess to say that it needs a complete rebuild.