1991 mercedes 350SDL loss of power question

I have a 1991 Mercedes 350sdl with 340,000 miles after getting the turbo rebuilt i have a loss of power problem.

hello scotty love the videos, I have had a loss of power problem for over 2 years with my car. When i first bought the car 4 years ago it could keep up with most things on the road, but after having the turbo rebuilt i have lost around 20-30% power. I put a turbo from ebay with low miles on it and the rebuilt turbo both with the same loss of power. This leads me to believe that the loss of power might not be directly related to the turbo. i was wanting to know if you had any insight on this issue. Thank you for your time.

never buy used or rebuilt turbos really, too much of a gamble. But do try a compression test of the engine first, could be it's just flat worn out inside.

Thanks for the quick response ! mechanic did a compression test right after problem and all 6 cylinders were good. when i pulled it up to the mechanic to take the turbo off because of the oil leak it ran fine and had all the power in the world, when i drove it home from the mechanics it had lost the power. the sudden power loss is what makes me think it isn't a wearing out problem.