1991 Metro back on the road - thanks!

I posted a couple of times but spent more time doing searches and jotting down information. It's pretty cool when an inexperienced fella like me can rebuild a motor based entirely on information found in this forum on the internet.
So thanks to the folks who asked all my questions before me and thanks to all the fellas with experience who shared their knowledge.
I think my buddy's got a pretty good little car right now and I enjoyed working on it.
I am curious though about 3 filter looking things connected up to the throttle body and intake manifold.
One can's mounted to the firewall almost dead center in plain view - a hose coming in and one going out with a white nylon adjust screw some leads coming off the top of the can.
Another's under the air cleaner - just sitting there with a line in and a line out. A little smaller that the can on the firewall.
The third is under the air cleaner as well and looks a lot like a little in line gas filter.
Thanks again!
Mike

Its hard to tell without pictures but here it goes:

The one on the firewall is more than likely the valve that bumps the idle
up when the ac is turned on. It's black with a white scew.


The black one under the air cleaner, is just an empty plastic canister that goes between the air filter and the ISC valve. I believe its called a "silencer"?

The blueish colored one located further down, it the ISC valve. and
should have wires attached to it.