I been thinking this for a while until I came in from 250 mile trip. It now has a slight miss, nothing eng shaking but a pop to the exhaust. It is stock for the most part. Have not done anything to it but service it. It sets in the garage for the most part, only has 60k on it. My first thought is injectors, which it does roll black smoke when you get into it. The only other think I can come up with is valve adjustment. But if its making a slight pop it would suggest a tight valve which would mean valve sinking into the seat. Any thoughts? Thanks    

Could the turbo charger oil to the bearings be leaking into the exhaust? How many mile on it?

Its only got 60k on it. Always let the turbo cool down.

 

Any instances with Hard Starts?  Injectors are relatively easy to pull and you could send them off to have them tested.

I would check the valve lash but you're correct that it's likely good. 

 

When was the last time you ran a fuel injector cleaner or towed heavy with it?

Michael Nelson could narrow this down for you. You could also call Source Automotive since they have exhaustive experience. No pun intended.

 

Talk to Rip @503 654 9009. They will know what to look for.