Ive had this whistle for a few months, and replaced the PCV valve a few weeks ago, because that was the only diagnosis I could find online. I had done the flame test and it indeed was sucking in, and post repair it does not suck in anymore. I understand this to be normal behavior.

However that did not fix anything. The whistle is still present and i have located the noise to be near the throttle body. I tried a starter fluid test and got one high rev but was not able to reproduce.

What I'm asking is, has anyone had a similar situation and how did you fix it.

Thank you very much in advanced!