throttle position ringing
 

So I purchased my 2007 rx8 about 3 months ago and ever since I've owned it, it has created a high pitch ringing noise under low acceleration. It doesn't matter the gear or the rpms. It seems to go away when not in gear. The only thing I can pair with the ringing is my throttle position, at the same gas pedal position everytime I hear the ringing. Is this normal? also my car is completely stock.

by induction system do you mean everything up to the throttle body? I've gone over my intake a few times and haven't found anything.

out of curiousity, what actually causes the sound? and why only at a specific throttle position? instead of a specific rpm or something

Check the tube that connects under the throttle body.

If you have the sound tube disconnected or an aftermarket air intake, chances the fitting is capped off.

The cap could be cracked.

So after doing some research on the vacuum system i vacuum tested the three tubes that come off of the accordion and two of them were holding a vacuum of 15 or right above 15( the rubes with the white and yellow lines), while the third was only at 7 (leads to what appears a catch can under the extension manifold), Is that right? also when I unplugged one of the tubes (one with white line) it made a ringing noise which i've never heard before but am thinking its the tube for the jet air system, which when plugged back in the noise went away. Understand this is NOT the noise I have been talking about, the noise my car makes is only at a very specific gas pedal position, and i've recently noticed that when out of gear with the clutch out my car will make the noise as well. Also I did cap the port that is under the TB, it is not cracked. Maybe this is simply a typicall noise?

there is a short tube coming from the rear of the UIM, it goes into the "vacuum" box thing underneath that u were talking about.

make sure that little short vacuum line (it has a check valve on) is connected/not broken/cracked. One of my friend's car recently had some noise like what u said, then I found out that little hose back there, for some reason, was not connected. Plug it back and the noise went away. but due to age, the hose was very lose, gonna replace that with silicone hose later for him.

hope this is ur issue

I checked this tube and everything seemed fine, it was not brittle or anything and was fully plugged in. Since this had me in a position with my head close to the UIM I noticed that it sounded like air was escaping from somewhere, but on second thought i just assumed I was hearing air coming through the intake system. So all those vacuum hoses seem to check out. Any other recommendations?

Some additional info! I just took the car for a drive and now notice that I can hold the gas pedal at the position to make the ringing, and the ringing goes away around 3750 RPM, everytime! I've never noticed this before. Is their a component that changes at that RPM? Does the induction system change what it is doing around 4000 RPM?

So does that mean I need to clean my SSV? any possible reason that would make the ringing go away? Sorry for the questions I'm new to the rotary world.

No, if I understand the purpose of the SSV correctly it allows more air for the engine once the secondary fuel injectors kick in. So with it closed and the ringing does that mean that the air is just creating a sound as it comes across the closed SSV?