I do have same issue (2002 toyota corolla 1.6 manual, Philippines, we bought it 2014 with 195,000km and runs good) but only same with nagykaldi when revving up, 2100 rpm above knock or rattling occurs regardless of that speed but could disappears somehow when I push (or they called as Wide Open Throttle) more or stay more with that rev level but still always turns back. I think I'll go with fixhexpo suggestion first. That is try to load higher octane (because I already tried 97% this 2 years ago and it works but does it totally repair the issue, maybe not it's just octane I think) or I/you may stay with lower octane and try (WOT) that high rpm, speed (90 to 100 kph I think) and gear selection (3rd I think). This could blow away such carbon build up, it's too bad that I rarely hit 2000rpm due to fuel consumption I always want to make more way to lessen the consumption of our corolla which probably led to this carbon build. Roughly runs 10-11km/Lit at city and I'm not so sure at highway but it runs like 17-19km/Lit.
It's been 4 years since I'm driving this car (I'm a light pedal driver) and rarely hit high revolutions always keeps it only about 1600 to 1800 in city drive (no knocks or rattling sound), but somehow I do in highways only and rattling occurs. I'm going to observe what happen if I'll try his suggestion, and give some more WOT for our corrolla.