Well, its gone (!?!?!?!?). Maybe bad gas? After filling up again today at Mobil with good old 93 octane, drove it to Alpena and back (about 220 miles round trip) and well, its gone. No more knock.
I did get this sound clip of it this morning before it went away. Sorry for poor quality, it was taken with an MP3 player from my drivers window:
click me
Note how it smooths out above about 1100 RPM this morning. Each time I turned off the car, it would only make the noise at a lower RPM.
I am running a superchip which advances my timing, so I'm assuming poor gas would probably cause it. Sound right?
EDIT: It does, however, still idle like crap. Not a strange noise, but it sits there and stumbles all over the place. Could the bad knock have maybe fouled a plug (I don't know what that means, but seems like it would cause bad idle)?
