New member requesting help with 96 3400 egr

Hey guys, Brad here.
Trying to sort out some issues with my tacoma. I have lurked and snooped on all the forums i could before i finally just decided to join and summon the help of the community. All of my searches have been pretty fruitless.

So here it is, My tacoma is a 96 v6 3400. I am attempting to correct a p0401 CEL code, as well as a p0420 Cat efficiency. I believe the cat efficiency code is subsequent to the EGR fault, and will probably go away once the "EGR System" is fixed. I understand there are several older models that have no real EGR. The truck has NO egr as best as i can tell. There is a blank on the right(driver's side exhaust manifold) where there COULD have been an egr port, but it is solid. The same is true for the back of the upper intake manifold plenum - another EGR blank, with no open ports or screw bosses.
I know there is an idle control valve that is broken, and should have 2 or 3 vacuum hoses connected to it, but i'm not sure how they fit in with this engine's vacuum system. The vacuum diagram under the hood, and every other 3400 v6 diagram i've found shows that there should be an egr valve and vacuum port thing.
I have to the best of my ability replaced any open vacuum port/ diaphragm cap etc with new hoses. The old vacuum hoses were falling apart, and some ports were just completely open with no hose connected. Regardless, the truck ran fine but obviously that's not going to make the CEL go away. In the process of replacing said hoses and capping off a port or two, i came across two open connectors. One behind the throttle body near where the egr vacuum port should be (the ufo shaped diaphragm with 3 vacuum ports on it), and one behind the right(driver's side) head kind of near the lower intake plenum. Also the two vacuum ports on top of the Throtle body labeled "E", and "R", both have absolutely NO vacuum. I stuck a vacuum gauge on them both and there is no suction from them.
I'll add photos to show where the hoses are now, and hopefully someone can point me in the right direction.

Another thing i found is that my fuel damper is connected straight to the port on the back on the intake plenum. In several photos i have found that there is a small metal vacuum pipe that runs between the two plenums and the fuel damper connects that to the square shaped plastic resonance chamber on the intake boot... mine never had that.

What i will say is this, my father did have the engine in this truck replaced about 5 years ago.. I BELIEVE it was from the correct model, but I have no explanation for the unplugged ports and missing plug connections.

Hopefully these photos make sense, All help is greatly appreciated!

 

I like the posting time

 

Thanks! that was really helpful...