Have you checked Bowden cable adjustment? Should be just all the way out with no compression of the spring at idle, it goes back in as the throttle is opened. Mine was WAY out, in an attempt to mask the vac problem.

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!