You need to troubleshoot the fuel and ignition system for the rough idle problem.

You may need new plug wires -- they are often fine unless distrubed, when they crack and start to missfire.

You could also have some vac leaks -- check all the vac lines and verify that you don't have a vac leak in the new headlights if you have hte vacuum leveling system.

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!