Yes, apply vacuum directly to the little turret on the IP. You should see the stop lever move as you apply vacuum.

What o-ring is leaking on the IP? If it's leaking fuel at the base of the injector lines then, you need delivery valve seals. If it's leaking oil from the stop lever shaft or control rod sensor or some such attachment to the IP, that has no influence on fuel delivery or valve lash adjusters.

Sixto
93 300SD 3.0