What is this piece?

[jdanda at sunflower.com (James S. Danda)]

On my '86 16v there is a 'gizmo' under the battery that is in-line between the air intake and the air box. It has one vacuum line and a tube running from the exhaust connected to it. It is obviously part of the air intake system, but I have no idea what it does. My only guess is that its an air-preheat, which makes no sense to me.

Anyway, I am having a hell of a time troubleshooting a big hesitation while accelerating off idle. While inspecting for vacuum leaks I noticed this 'gizmo'. I looked through bentley's and could find no reference to it.

Thanks,
Jim