I had a chance this morning to do some testing. It seems like my issues come on at a certain engine RPM. This is true even in Park or Neutral. If I'm idling in park (17 Hg vacuum). I take it up to 3000 RPM (This is around where I encounter the drive-ability issue on the freeway). I let it return to idle and its extremely rough running (2-5 Hg vacuum). If I then slowly take the RPM up to say 1200 it smooths out and then will idle as before (17 Hg vacuum).
Can this be transmission related being that it happens in park? I'm at a loss. My ignition system is pretty fresh meaning Pertronix ignition, plugs, wires, cap, rotor, coil. all less than 7500 miles.