I've noticed that at speeds above 65mph, only if the A/C is on, I get a high pitched whine that last a few seconds. The sound goes away completely when the A/C is off. Has anyone else that's experienced this know of what might be happening? I still have my warranty but haven't had the time to take it in yet.

 

My car and a few other people's cars have similar problem. You can take a look at these threads:

https://acurazine.com/forums/2g-tsx-problems-fixes-145/high-pitch-noise-light-acceleration-896155/
http://www.tsxclub.com/forums/2nd-ge...eleration.html

Someone in tsxclub reported that adding Freon solved the problem.