3rz Rough idle and stalling

I have a 88 4runner with a 96 3rz swapped into it, and it recently started running really bad. When i start it up i have to instantly put my foot on the gas otherwise itll die, this has been fairly normal for a while just until its warmed up (probably something to do with my crappy Amazon "cold air intake") but the past few days, ive had to keep my foot on the gas at all times unless im in gear. Meaning it stalls while shifting, at stoplights, or pretty much anytime it wants to idle.

Im getting codes every once in a while for p0170 which is fuel trim malfunction, if i remember correctly, it means something with the maf is wrong, but i replaced it with a known good one. So i just decided to try and change the fuel pump because it would have to crank for like 30 seconds sometimes just to get started up. That fixed the long crank issue, and now it starts up instantly, but it still has the issues with stalling. When it does idle it idles really low and will be very choppy like an up and down sort of sound almost like it has really big cams.

I have no downstream o2 sensor which ive heard is fine but ive also heard it can cause issues, would this be causing it? I dont have a cat so if i put one in it would just think that my cat is blown out. I get code p0141 but i havent looked into it too much just because i was told the downstream sensor has nothing to do with engine management, i have no idea if thats true or not though.

This to me kind of sounds like a vacuum leak sort of situation, but its weird how it got worse instantly instead of over time. Could it be some sort of issue with the TPS? Or the IAC? Could it be some sort of bad ground? Im just looking for some oustide input because this issue has me stumped.

 

Hey I got a pretty much the same issue, just wondering if you made any progress with it?

 

No, i turned up the idle a bit just so that it wouldnt die and that helped a lot of it, but it still isnt running quite right. I am really thinking its vacuum related but i dont know where its leaking at.

 

1999 Toyota Tacoma IAC valve cleaning or replacement