Knock Control all over the place

[currancchs]

Car (2008 TL-S MT) is stock, other than a longtube J pipe (RV6). I bought the car needing a clutch and timing belt and did both - no apparent issues with either system since the repairs (about 750 miles on them). I have been waiting to tune until I can log the factory tune enough to be comfortable knowing what to expect, but am using Hondata for logging.

I also replaced the purge valve (due to a message stating to check gas cap that repeatedly popped up - haven't seen it since changing out the purge valve) and cleaned the throttle body. I am still seeing nearly 20% positive fuel trims on bank 1, although they fluctuate between about 3% and 20% (short term, long term is about 15% - bank 2 is 4%, with STFT hovering around 0).

When I first began logging, knock control was 98-99%. After a few days, it went down to about 50%, but kept dropping, all the way down to 10% or so. Car ran great that way and felt peppy with no audible knock (I was running 93 and ran a bottle of Redline FI cleaner in the first tank). Car ran like that for a few weeks (no WOT, as I was breaking in the clutch nice and easy). Hardly any knock retard showed up during even stop and go traffic.

The last week, knock control went back up to about 60% and this morning jumped from 60% to 98% in a very short span of time (under 5 minutes) during stop and go driving. Car felt sluggish and knock retard was going up to 10-14 degrees, repeatedly, on takeoff/gear changes. More throttle (still in CL the whole time) resulted in more knock retard (did not go WOT and don't really want to until I determine if something is mechanically wrong or not).

No CEL of any kind.

I hate throwing parts at it, but it seems like the engine can't be knocking horribly, then not at all, then horribly again without me doing anything to it unless its a faulty sensor, but no CEL and the car acting up when knock might actually be expected makes me believe it might not be the sensor.

I will be smoke testing the evap system tonight and have already ordered a knock sensor and intake plenum gaskets, but does anyone have any ideas?