Very interesting phenomenon.
When the butterfly is wide open, the actuator goes nuts, creating a flutter with the damper, you can close it by hand, its quite, then it slowly opens and buzzes again.

It started out with a buzz no buzz sound, then eventually turned into a constant, non-stop, buzz.

The ORM has solved the problem, and saved me $300 for a new FCV.

I did not see anyone else with this problem, so I thought I would post some info on it.

ORM: check engine light on? - that just means its working

I too had this problem with the EGR FCV just last week. I'm still under 36K so the dealer replaced it without charge. Since then I have tried the ORM and am truly amazed at the difference it makes.

good timing for you, I am at 55K so they looked at me and laughed ..warrenty what??