I have a 08 tC and i have had my CAI, and headers installed for over 1 1/2 yrs now. Over that period i have heard what sounds like a high pitched whistling always the same frequency definitely coming from somewhere in the engine bay it is every now and then so I figured at those times it was no or big deal blaming it on other cars passing me. I started noticing it more, not that it was getting louder or more often, just i knew what to listen for. So whenever i came home i would roll down the windows and see if i can replicate the prob. When its in neutral its only noticeable when i barely tap the gas, not if i hold it in at any rpm. In first gear it hardly noticeable, very quick, my exhaust overpowers the sound. In every other gear (especially when i have the windows down and the whistling has a barrier or a building to bounce off of i can hear it perfectly) when vacuum gauge is in between 15 - 10 inHg the whistling is constant, if i go above or below that it goes away or probably s db i cant hear. I have checked, double checked and triple checked all potential points of leaking on all my mods but it is really hard to do in neutral and listening for it over my exhaust but theres always a possibility i have missed something. Can any one provide me with some incite or do they have the same common sound with their mods? Helpful ideas, comments, suggestions? Or if any one is in the Mississippi area (I'm tdy so ill only be here till June 4th) can listen and help out? Thx!!

 

LOL thats not a vac leak its the way our throttle body is designed the sound ur hearing is the air going through a tiny opening in the throttle body our car is famous for that sound

 

it gets louder with intakes btw

 

dude i hear the same thing!!!! but only when i let off the throttle....oh wait thats my BOV... lol... JK.

^^ hes right its your intake

 

yea man it is the intake, i just put a cai on and it does that high pitched noise whenever i just barely hit the gas.

 

Oh man at least i know im not alone in this, i thought for the longest time i was going crazy cuz i just couldnt find where it was coming from exactly! Im actually looking to get a Dezod turbo kit here soon im hopeing that i still wont hear it any more if and when i get it cuz it drives me nuts!! So you all agree no vacuum leak and wont cause problems later down the road (lack of performance, or gas milage)?

 

no problem...and even when turbo u will hear it...its from the way the air crosses the throttle butterfly

 

You guys are awesome, i really appreciate the help!! So basically the only way to get rid of it is to change the throttle body with an after market one (if and when i go to a bigger size)?

 

i dont think that will help either...most newers cars do this,.,.

 

turn the radio up for roll up the windows.

 

what do you mean that sound is great

 

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This is the EXACT issue that I'm dealing with and I know I do not have a vacuum leak. How did you fix this issue? The whistling is definitely throwing an emissions error code, so my check engine light is on.