Interesting, I purchased my '09 2 years ago and I seem to remember it always being there but did nothing about it till my extended warranty was expiring for a final once over at the dealership. As much as possible the top is down which makes it very apparent if no music is playing, have just chalked it up to a nuance of the car and normal. I figured it was something in the intake path causing the sound as it seemed to be based on throttle position / air flow rate. Tomorrow if I get a chance I will see about re-creating while idle, maybe we have the same thing though maybe not.

 

Does your car have pse? My car had the same issue it was a cracked weld on one of the exhaust bands that hold it in place was so annoying and common.. I almost 100% can guarantee this is what your experiencing $20 fix

 

No PSE, have a Fister bypass. I'll check all the welds on the exhaust just to make sure. One thing I've noticed is that I can hear it a bit at idle now. Should make it easier to diagnose.

 

Any update on this ?

 

Haven't checked the exhaust yet, but getting a new serp belt today so I'll try replacing that (original belt already at the recommended replacement interval). Will update later tonight.

 

Checked the exhaust, no cracks on the connection bar between the two pipes (or anywhere). Changed out the serp belt to a new contibelt, no difference. Since I've been able to hear it without load now, I will try to probe around for the sound.

 

Update: I removed my Fabspeed CF intake and threw in my stock airbox. Now there is no more squeak (I checked to make sure the Fabspeed intake was not rubbing on anything that would cause the sound). This leads me to believe that the stock airbox is masking the sound, not that the Fabspeed intake was the cause of it.

As a test, at idle I opened the oil filler cap and the engine started to idle high and rough. I could also hear a loud hiss towards the right side of the firewall where the AOS is, so that might very well be the cause. Idled so rough that it triggered a CEL (fuel trim out of bounds). Will grab a manometer and check (over 5 inches = bad?).

 

According to Tony Callas - The proper reading for a healthy AOS is 5" of water column, and this can vary up to about 6" and the unit still be ok. If the values are higher than this, then the AOS is failing.

The value is elevation dependent. I think the 5" is at sea level. The equivalent in Raleigh, NC is 5.5" (according to my notes).

 

Thanks for the tip. I'm at sea level, so I'll start with that as baseline. Waiting to get a new oil cap and a manometer.