1995 E300D Speed Variation Problem

[shertex]

My newly-acquired 1995 E300D has the following symptom: mild oscillating speed variation when going at constant speed....as if a valve is opening and closing when it shouldn't be.

According to the PO, the pressure control valve (vacuum operated, next to the EGR) is operating strangely. My hope is that that's the problem.

My plan of attack is, for testing purposes, to disable the EGR and that valve control and secure that valve in a full open position per http://www.peachparts.com/shopforum/diesel-discussion/219264-easy-reversible-egr-delete-95-96-97-non-turbos.html. And to replace both fuel filters. And then see where I stand.

Any other ideas? Jeremy5848 has already given me a lot of good advice....but I thought I'd see if anyone else has thoughts and create a thread for any who have similar problems.

Thanks.