380se idle issue

[sm63racing]

I have an issue I really don't have a direct explanation for... I have the air cleaner off, and when I apply a small amount of pressure to the control plate, preventing it from closing completely(open roughly 1/16 of an inch), the car fires up, idles, and revs strongly. If I remove my finger from the plate, it immediately dies.
The only explanation I can come up with is a vacuum leak, but as the issue seems to be not drawing enough air, wouldn't a leak somewhere actually resolve this particular issue? I'm new to the CIS system, and am still learning