Your EGR valve is stuck open! The huge clouds of inky black smoke and the funny rattle give it away -- too much exhaust in the intake and the fuel won't burn. You get lots of knock, but it sounds kinda muffled, enough smoke to stop traffic, and no power until you get the rpms up to where the exhaust gas ratio is right, and it takes off when the turbo comes up.

You can either replace the EGR or just pull the vacuum line and make a plate fit under the top of the EGR to cap it off -- when they stick they will sometimes also lift under exhaust pressure. Put the plate between the EGR and the manifold. You can make it out of scrap sheet metal (not aluminum).

My Volvo did exactly the same thing, huge pain in the butt on a long hill! I plated off the EGR, complete cure.

Sorry I didn't remember it at first!

Peter

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1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!