The 220D is less powerfull Engine then the later models.

When I got the Car on my Year and model acceleration was extremely bad but once speed was built up it drove normally. When you slowed down to a stop the acceleration issue was back.
It turned out the throttle linkages were extremely sloppy and the throttle lever was not getting moved far enough.
In the Mercedes Service Manual there is specific lengths for the linkage rods and is a few parts back to the acclerator pedal that can wear out.

More recently I was having inconsistence acceleration and the linkage on the fire wall was in bad shape. Replacing that fixed it.

I thought your year and model had a Fuel Injection Pump with Butterfly Valve that controls venturi vacuum in the intake Manifold and a Fuel Injection Pump with a Pneumatic Governor that has a Diaphragm inside.

If your Diaphragm has a vacuum leak you would get smoke because that causes more fuel to be injected.

However, over time the Diaphragms get stiff. I am not sure what symptoms that would cause. Also one side of the diaphragm is exposed to the air and if the vented cap is restricted the Diaphragm cannot work correctly. (Just remove the vented cap and drive and see if there is a change.)
There is threads on replacing the diaphragm.

Restrictions in the tubing to the Venturi.

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84 300D, 82 Volvo 244Gl Diesel