Hi folks,

 I've noticed something interesting on my 99 Altima.  Under the throttle
body there's what I'll call a cam, that the throttle plate mechanism rests
against.  It seems to allow the throttle to rest at different angles, i.e.,
it allows the throttle closed position to change.

My 94 doesn't have anything like this, so I'm wondering what this is for.
It's spring loaded to return to a preset position, and it feels like there's
a cable attached to it underneath that runs inside the throttle body.  Is it
some form of idle speed controller?  My idle seems a little too high (sits
about halfway between 750 and 1000 rpm on the tach) so I was wondering if
maybe this might be out of adjustment, or stuck.  I couldn't get it to move
by hand.

I can't find any mention of whatever this is in my new Haynes manual...
they seem to have left out a lot of the changes between 94 and 99,
conveniently enough.