The more I think I understand this car...The more I realize I don't

[Fourkguy@aol.com]

Hey Guys,

Maybe someone can help. Thought I had this one licked, but it's back & worse.
Rough idle, drops to 800 RPM then back to 1000 sometimes bad, sometimes not,
usually once, sometimes multiple times when clutching approaching a stop, etc.
Engine groans a sick sound as well at appx 3000 RPM. Seemed cured when I re-
gapped 2 of my 4 Bosch triple electrode plugs. Only one electrode on each was
gapped way too small and had black deposits. Problem is back & better than
ever.

Questions:

How to test / clean or otherwise verify ISV
How to check for vacuum leaks
Is dipstick seal, other oil system related vacuum leaks an issue here (86 4KS)
Anything else to check?

If sparkplug gap had effect last time, seems maybe all ignition related
components should be checked. Any suggestions? Comments?

TIA

Jeff