weak detroit

Did you check the fuel filter for air? How's the blowby look?

 

First thing you want to do is, take a flash light and with it running look into the fuel tank you can see the pick-up and return tubes, look for air, if the fuel is dark it is compression if clear it is sucking air.
second check the fuel preasure, it should have at least 12 at idle and 60 at high idle,
Third check the CAC, intake manifold, and if you have acsess to a laptop check the boost sensor and the operation of the waist gate.
Just a thought!

 

Flashed with what and what turbo?

 

check the bullgear!!!for timming if yo never chance if is original 01 good luck!!

 

Without knowing the history, yes it could be out of time if someone put it together wrong. It is not physically posssible for it to jump time on it's own without something being very broken.

Personally, I'd check the CAC, hoses and piping for leaks and check for bubbles in the return fuel. Since the engine was swapped, make sure the proper fitting is in the back of the head for the return fuel. Check fuel pressure. Once you check all the basics, you should verify cam timing, you'll have to pull an injector for that, so start with the easier things to check 1st.

Did you do a valve adjustment on it? Intake valves on those tighten up over time.