My vote is pinging due to the mention of octane boosters.
Not an expert in Toyota Engines, however, most modern vehicles have what is called in laymans terms 'knock' sensors. Usually two of them on V engines, one on the left bank and one on the right bank. They detect teh high frequency ringing that occurs when the air-fuel mixture predetonates on compression (before the plug fires).
Generally the tests of these sensors can range from 'replace with known good' to a simple resistance check. Also, in some cases, a small amount of pinging is actually considered normal. But not a prolonged ping, as that can destroy an engine. So if it only pings say pressing the accelerator but the ping tapers off to almost none, you may be in one of those marginal vehicles.
The first place to look is the actual static engine timing at idle, make sure it's in spec and not tweaked up a few degrees.
The second place to look is the ensure all teh vacuum lines are 'right' and go where they should. Most cars have a vacuum advance circuit. If that is not working well, it may be advancing too much all the time (the static test might show higher advance, and teh vacuum system woul dbe the next thing to test.
After that - look for vacuum leaks that might lead to lean burn conditions by checking plug color - lots of references for 'proper' plug color on the web. The benefit of popping the plugs out and looking are many: one plug may be burned/discolored enough you know which cylinder to chase in the next step.
After no leaks, then might be an injector that isn't flowing well. Use a long screw driver or stethoscope to listen to each cylinder to find the culprit (if ping can be produced standing still, otherwise see Arab 2'wheel manual for how to use stethoscope at speed...
The last place to look are the knock sensors... or do this earlier if the test is a simple resistiance check.
