Weird noise on my Z

[1stoptuner]

Its weird how it started last night. Its some squeeky noise whenever I'm driving. It goes on and off and I parked my car after I got off work in my driveway and popped the hood and it sounds like its coming from the engine or under it. When I revv it it sounds really scratchy/squeeky not deep like before. I'm thinking it could be my test pipes but I've had them on for 3 months now.