High pitched whistling at higher RPMs

[Towncivilian]

I was driving my 2001 3.5L SE Pathy and floored it through a yellow and I heard a loud whistling noise coming from the rear of the vehicle as RPMs were rising (was louder as RPMs got higher). This happened several other times as RPMs got above about 3k, but it was not nearly as loud. I haven't heard it after that one driving session. I recently changed the fuel filter and both cam position sensors (to fix P1140 and P1145), the former done myself and the latter with a friend's help. No SES light currently. Does anybody know what it could have been?

[miamiheat3332]

hmm, whenever i punch it into the higher RPM's im pretty sure i do hear a high pitched whistle, but im pretty sure its the engine sucking in tons of air, and it sounds pretty good too.

[Towncivilian]

Makes sense. I guess I just never noticed it before, just wanted clarification that this is a normal thing.

Thanks.