Some food for thought, stock STI does not listen for knock below 0.9 or 1.0 load, depending in which direction you're transitioning in or out of the listening range. What are your threshold set at? Before everybody jumps down my throat on how crappy the stock tune is and all that, the low load timing maps are not that bad. So, why Subaru would do that? It's possible that the sensor may be picking up lots of false knock under low load due to resonances in the engine bay and sounds being interpreted as knock. The knock sensor is nothing more than a microphone whose signal is fed into an analyzer that looks for knock signatures in the feedback. OP, search for false knock. You'll see many threads of people pulling their hair out about this. Low load, cruising situations, crazy FBKC. Makes no sense. Some anecdotal evidence, I tried lowering my listeing thresholds down and it produced exactly what you're describing. My logs started to show major knock events and ECU constantly pulling timing at loads <1.0. ECU would pull timing, more knock, more pull, more knock. That was a year ago. I went back to stock level thresholds as there seems to be more to it that meets the eye. I am actually willing to give Subaru the benefit of the doubt on this one. Now, I am not saying that you're fine. Just pointing out that it's possible that you're chasing a ghost. But, you should investigate to make sure you don't have a problem. If you have an EGT gauge, look at your temps during those events. If they're high, you may not have enough timing.