Throttle Body Squeaks

[Sack35]

Hey - looking for input on this one:

When I tap the gas from idle, I hear a quick squeak before the revs climb. Sounds like one of two things:

1.) the valve in the throttle body (Correct me if I'm wrong: by throttle body, I mean the part of the engine that the intake tube connects to) is scraping against the body itself. However, I pulled off the Z tube and checked the throttle valve - it doesn't seem to be contacting the body.

or

2.) air getting sucked past a closed valve - maybe caused by the vacuum created in the split second after hitting the gas and before the throttle opens up. The noise isn't there if I ease onto the gas.

Also, during low end acceleration (under, say, 3000rpm), I can hear a longer, higher pitched squeak (sounds like a dusty brake) that stops when I let off the gas.

I noticed the first noise right after I put in the Z intake 3 months ago. In the last week or two, I'm noticing the squeak during acceleration.

Other relevant info:2003 6MT G35 Sedan, ~20,000 milesK & N Filter on Stock airboxStretched "Power Duct"

Anyone have any idea on what the hell is happening with my engine?

Disclaimer: Did a quick search and found that maybe this kind of thing is relatively normal on some of the smaller nissan engines. Didn't find any comments on VQ35's, tho.