The battery has not been disconnected, since the radio did not ask for a code. The knock sensor is still in place.

I spoke to a friend yesterday who happens to be a professional mechanic, and he informed me that the phenomenon was called tip in knocking (if I remember correctly). It is not really dangerous since it goes away at full throttle.

After asking me to verify the knock sensor, he thought it may be as simple as a bad tank of gas. I am a cheapo and fill it up with 87 octane, and anything below that would probably give the engine some trouble. I'll get over to pep boys and will buy a can of octane booster to see if it goes away.