PLease see the PM I sent.
I had the same problem when I bought mine I have a Fedral Mercedes. This is reasonabley safe to do: Remove the plactic that covers the 2/3 way valves (mine has 2 valvs). When you take the slop out of the linkage you do not want the plactic Cam that opens or closes the valves to move.
Where the rod attaches to the fire wall is the rubber part that the linkage rod goes into rotted or ok. If it is OK follow the rod towards the front of the engine and you will see a small bolt with a 10mm head. Loosen that and you will find that there is a kidney shaped slot that you can pivot the rod around in until you take up some of the slop and tighten the Bolt.
The next place I went to was the rod that goes from the throttle arm on the Fuel Injection Pump to the linkage above it. (Your Idle speed should be properly set before you do this.) I pried that linkage rod off the ball on the upper linkage and adjusted the rod to take out the excessive play. You do not want to adjust the rod so tight that your that it effects your idle. Meaning that you must leave enough play in the linkage so that the the Injection pump throttle lever can return to and make contact with the idle screw stop.
And that solved most of the problem for me with out interfeering with the other linkage rod adjustments that are mounted on the Valve Cover.
You can adjust the rod comming from the Accelerator pedel to the part on the fire wall to take up some slop but on my car I could not adjust the rod anymore.

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84 300D, 82 Volvo 244Gl Diesel