You need to look at any connection point on the intake system after the MAF, including the MAF O-ring seal. All those lines that connect to the accordion tube. The one you might might want to check is the the jet fuel mixing nozzle line in the diagram above that connects to the bottom center of the LIM just above the exhaust manifold. There’s a rubber hose there that connects to a metal line then back to a rubber hose to the intake accordion. All those other lines in the diagram too; the VFAD nipple, the solenoid vacuum tank nipple. You should pull a vacuum on the solenoid valve tank and make sure it holds vacuum; a stuck solenoid or bad solenoid nipple seal will cause an unmetered air leak and the intake valves also won’t work properly.

Well if it’s not receiving extra intake air it might not be receiving enough fuel; primary injectors or fuel pump/internal filter

Unless it’s the primary injectors, fuel pump is a long shot though

I hope this gets figured out...Im having the same problem. Lean conditions. Installed new fuel pump, MAF, plugs, wires, new(ish) Eshaft sensor. Still the same. Changed upstream 02 sensor with a known working one (used). Same thing. Checked for vacuum leaks and VFAD nipple installed
I did just install an ebay intake and currently waiting for a mass airflow straightner. If that doesnt work, then im sending my injectors to be rebuilt with 40% more flow.

Once I get back to the car, Im going to disconnect the barometric sensor and see if it changes anything. After that Im stumped.
https://cimg4.ibsrv.net/gimg/www.rx8...6365bfb842.jpg

https://cimg1.ibsrv.net/gimg/www.rx8...1b5279e2ee.jpg
Whoa! Barometric meter is $150+. Looks like I'm checking craigslist for that. Then I guess injectors rebuild. Please let us know if you get this figured out!

Do not increase the injector output, the computer will not be able to compensate for that and the car will not run.
Go back to the stock intake for kicks. There's a thousand threads here from owners who install random modifications and find their car doesn't run. There is nothing to be gained by upgrading the stock intake.

I didn't see ignition coils on your list of recently replaced parts, definitely look into that. They aren't reliable beyond about 25,000 miles. And don't buy ebay knockoffs. NAPA has good quality OEM replacement coils.