Latest update:
Problem seems to be getting worse as I'm starting to see an increasing incidence of low load knock in the 1800 - 2900 rpm range. This morning it knocked (3-4 sustained counts) every time I'd go through the 1800 - 2900 rpm range. It would even knock if I'd blip the throttle in neutral. After driving for a few minutes, it seemed to settle down.
When I reviewed my logs, it doesn't appear as though I'm too lean as my O2 voltages are 0.89 V with the TPS @ only ~45%. I can't hear any knock/ticking. The only thing I can hear is what sounds like regular valvetrain noise. Just to be sure I wasn't getting the dreaded rod knock I sent my oil away for analysis. Analysis was normal, except for the fact that I had slightly higher levels of iron or aluminum. Apparently this is from my top end, but they said this could be normal if I am racing my car. However, I'm not sure if driving a car like its stolen on a daily basis counts as racing...
I was pretty late with my oil change, so maybe this also had something to do with it.
Next weekend I'm going to change my wires (finally) so I'll report back if it helps or if the low load knock gets worse.