problems with detroit , houston area

Did you change fuel filters. If so make,sure the O rings are ok and thr spin nut to clamp the bowl didn't get crossed threaded

 

Does it start hard. Before starting . look and see if there is fuel in the plastic bowl. If not then someone goofed putting on new fuel filter. Trust me, I've had it happen no fuel means an air vent in the system. Also look and see when running if air bubbles in the fuel. If that then the check vavle is bad in the fuel filter body

 

Fuel pump O ring. If it is taking in air, you aint gonna get power.

Intercooler line clamps to turbo. If you caved in a clamp the overall air to engine sucks. (Pardon the pun...)

 

Eh, just ideas. Ive had a few pumps burn through when the seals broke. Result is a 10 mph sick doggie crawling to shop. Any sort of water kills it. There is a story somewhere in my thousands of posts about it.

Somewhere somehow you will find the real problem.

Engines need fire to run, fuel to get it. Air to breathe to burn and compression to light it.

 

What are the RPMs like? Can you throttle the RPMs higher than about 850? I'm assuming during the rebuild the valve lash got adjusted...or when was the last time the valves were adjusted?

 

I'm wondering if you have a fueling issue caused by the injectors as well. You could have a multitude of issues.
Seized injector, broken tip, cracked injector bodies.

Are you getting excessive black or white smoke? Maybe you're getting excessive aeration in the fuel?