Sorry for the late reply guys, I was away at school. So I removed the oil cap, sound disappeared. I got a replacement PCV valve and put it in, car sounded and ran fine until operating temp, then the original sound came back along with a terrible squeak. I'm assuming I either put the PCV in incorrectly, or I got the wrong pcv valve.

I realized after testing it, but I have a Gen V SC. Does it use a different pcv than a stock 02 GTP? I just picked one out based on my year and model.