Stalling issue

Kind of jumping back to my original posted problem, figured I would post this to say what I'm pretty certain the problem was, and to embarrass myself a little.
It's kind of a groaner, but it just shows the level I am at in regards to these things.
When I got back on testing things this year, I cleaned the iac, set the base idle and tps voltage. Still ran pretty crappy.
While I was in that area I happened to find a little black canister with a vacuum line on either side. I noted it was a bit oily on the bottom, and had some sort of material inside it. I didn't right then and there research what it was, I just put it back where I found it. I found it hanging out in the area of the throttle body.
I was kind of just starting to get into trying to learn what everything under the hood was. I happened to be getting a good top down view while leaning in far.
That's when I spotted something odd. A hole in the top of the engine. I know it's got another name. Rocker cover maybe?
Anyways, I was pretty sure that engines should not have open holes in them. Then I quickly remembered that weird canister I found a few days before. What do you know, fits perfectly into that hole!
IMMEDIATELY the engine ran great.
I reset the base idle and tps voltage one more time, and its been running like a dream since. When I was having those problems before, it was always way worse on hot days. Already had a couple scorcher, but no problems!
Rookie move I guess

There is some stuff in that canister that resembles a steel scrubbing pad, it acts as a catch for the oil that gets trapped in there. You can clean that out with carb cleaner; just remove it from the hose and spray it in there—don’t let it drain out right away—and after about a minute turn it right side up and let the stuff run out the bottom. It will be a lot of dirty dark stuff. Repeat until it comes out clear. Let it dry out, then reinstall it.