This issue is identical to the problems I had with my original motor in 2013. I was cruising down the highway one night and the car started to knock. Long story short - the dealer blamed me for racing that car and revving it to 8500rpm. I requested proof, and they couldn't/wouldn't provide any and pushed the repair through insurance. 7k miles later, the engine blew up (but it did have help from a Vortech kit and Visconti at that point).
For some background, I was having coolant issues since new:
http://www.ft86club.com/forums/showthread.php?t=36150
Blown engine story:
http://www.ft86club.com/forums/showp...2&postcount=28
Some pics:
http://www.ft86club.com/forums/showp...2&postcount=32
I'm not saying that your engine may suffer the same fate, but just keep an eye out for the signs and bring it to Toyota the second something is amiss.