83 300D power surge issue still happening!

[thatguyinky]

I have been trying to fix this issue for a month now. When driving the car the power will go up and down with no pattern to it. Up hill, downhill, turning, straight, UGH! It will start to accelerate properly then it will be a dog, but sometimes it works the way it should. Then all of the sudden back to being a dog. When it's running properly it runs great. I don't get it! I'm pulling my hair out!

Items I've addressed to try and fix this issue:
-Fuel tank removed, cleaned and new tank screen.
-New fuel filters
-New injectors
-Check vent line for blockage
-Blocked off EGR
-Checked tranny fluid
-Valve adjustment (double checked it)
-Cleaned the banjo bolt


I've been through a few tanks of diesel from different places, still does it. Could the wastegate be an issue? I have a used one sitting around I could swap. What other things can it be!

Thanks in advance