Stalling out wont idle have to stay on throttle
 

I know ive posted here a lot but im trying to sort this car out after a headgasket job. Anyway 2003 saturn ion sedan. The car now drives but when i let off the throttle it dies there is no effort to try to come back at all. When i give it just a hair of throttle it stays on and when i drive it pulls like its healthy but when i cruise or keep speed it wants to shut off like it sputters for a bit. The symptoms almost feel like a failing crank sensor and i get no codes for anything. I got one code a while ago on first start for cam shaft sensor. I learned for cam sensor codes you replace the ignition module which i did still same issue just no code.
Heres a list of things i replaced since the rebuild:
ignition module
spark plugs Bosch double iridium
all 4 injectors
intake manifold gasket
little boot that sits between TB and intake duct

im seeing people say O2, MAF, intake temp sensor, ect. What is the likely cause of everything i listed?

(Edit: The ignition module and injectors are AcDelco)

I would verify cam timing.

i would think since i lined up timing with the cloyes gear set that it would be in time and counted the links in between but i also had a shop do a valve job when they milled the head could that be the issue?

Vacuum Is highest at idle.
What reading do you get for vacuum down near idle with someone keeping it running with their foot on the pedal?

Suspect intake manifold leak.

this may just be the whole answer but there is a hole with what looks like 2 bolt holes around it that has nothing on it position on the driver side of the intake it looks like something is there but i cant remember anything being there could that be my issue?

First of all it is a speed density engine not a mass air flow system so be careful of what you read on the internet. Please check the compression since you installed the chain. It is possible that the valve job is not perfect. You might need to do an idle relearn since you have a drive by wire throttle body. My L series L61 cars are a cable throttle, the v6 L series cars are drive by wire and have idle relearn procedures.
Billy is the resident Ion guru.

its an ion with throttle cable i havent tested compression but compared to before how the motor sounded it sounds a lot healthier the crank sounded uneven before now it sounds even but ill see

Picture of hole which you mentioned above?

@DropDead you out there?

https://cimg8.ibsrv.net/gimg/www.sat...addd33655.jpeg

Ive done a bit more poking around and looking at numbers with the scan tool and figured the car goes for the correct fuel amount when under load for example when i give it heavy throttle numbers straighten out to 0 or within 2% of 0. But when i try to hold speed say 30 mph it would run down to -50% and it starts pinging like its running lean. A lot of smoke comes out the exhaust and it backfires when under heavy load. To me it seems like a knock sensor issue but once again there are no codes for it. I have reason to suspect PCM aswell seeing as there are no codes not even stall codes which its stalled several times and passlock activates often. Am i going down the right path to you guys?

(PS. When talking about percentages im regarding short term fuel trims long term trims are glued to -0.8% all the time)