I fixed the rough idle on the 87 300D by replacing the pressure valve holder seals on the IP. Probably didn't really have to replace them, as the majority of the holders weren't properly torqued down (#4 was only finger tight!).

Pretty easy job -- just remove the injection lines at both ends, remove the lock rings (the hardest part for me since one was siezed!) unscrew the holders one at a time and lift off the copper ring, put the spring back on, and screw the holder back down to approx. 30 ft/lbs.

Had to bleed the injection lines to start, but that's normal.

Car runs wonderfully now -- just a hint of vibration and diesel noise at idle, gone as soon as I touch the throttle. Big improvement over the dead cylinder thump I had before.

Now, if I can just be sure that the oil in the coolant tank is left over from a previous repair.....!

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!