Here it goes:

1987 300TD
Intermittent problem with surging RPMs.

Every so often, it just goes astray and I can pretty much keep it under control by jiggling the wire harness that comes across valve cover.

Obviously one or more of the wires is bad.

Would prefer to have some idea which one(s), before having to trace each and every one.

Any thoughts on that?
Appreciate any comments/suggestions.