Once the car is warm, it will emit a whistle sound at idle only and sometimes up to about 2K RPMS if I don't step on the gas too much (If I floor it, no sound). It is not consistent, however. Sometimes it does not emit the sound, sometimes it does. Sometimes it will sound for about a minute, and then it will stop etc.....It sounds strongest around the passenger side. If I take off the nipple on the front of the plenum (Create an air leak) the sound will stop after a second, then once I put it back on, it will come back. Also, if I shake some of the vacuum lines (In the general area of vapor canister purge valve), it will change the sound.

I am lost as to what is making this noise, any input?

Vid:



UPDATE!!!!

Lower Intake Manifold Gasket had a tear/ was deformed.
Replacement fixed the issue, also made my idle better.

 

It sounds like you have an air leak somewhere - if you create a bigger one (remove PCV hose) it stops leaking which makes sense. Tried a smoke test near the vapor canister purve valve maybe?

 

Which hose exactly would I use to smoke up? I am not experienced with vacuum leaks.

 

A vac leak just means its sucking air into the engine where it's not supposed to, so if you blow smoke near the leak you'll be able to see the turbulence and find the leak. You can use a professional smoke machine, a beehive smoker, a cigarette, a fat blunt... you get the idea.

 

I have done a vac test before, but I blew into a hose off of the brake booster on one car, I wasn't aware that you could blow around the area instead.

Thanks!

 

^^That's another (better but harder) way to do it, fill the whole thing with smoke and try and find where the smoke is leaking out. If the first way doesn't work you can try that.

 

You %100 have a vacuum leak. I had the exact same noise after replacing valve covers. After taking everything back apart I ended up finding a cracked hose. This isn't a video showing the leak, but I made a thread about the same noise

 

Darn, which hose was cracked for you? It may be the same one haha. and how did you find it? I don't suppose you just inspected every hose. all of mine feel good, not fragile.

I never had a car whistle due to a vacuum leak, so I was dumbfounded.

 

I pretty much took most of the intake apart including the plenum until I found a cracked pcv hose. Pretty sure the crankcase ventilation hose cracked as well. Take the engine cover off to get a better view of things.

Pcv hose

Got some heater hose as a temporary fix and ordered a silicone kit from z1.
You can see the two hoses near the plenum that look new compared to everything else