Car starts then idle just dies

[Domzz]

Hey guys.. So I did a swap on my NA z and after it turns on rpm goes over 1500 then right below 500, sometimes turns off sometimes stays on. I replaced the IACV and fuel filter, damper, pressure regulator. The fuel pressure is 45/50psi. When given gas it will rev and be okay. While driving it's okay as long as you're at high rpm if there's a stop sing and I slow down it shuts off on me. EGR was removed but I did not do anything with the ECU about it(is that bad for a 95'?) also ran ECU codes and there was no malfunctions.. What could it be?

[Rubyz32]

Sounds like a vacuum leak. If you have a vacuum gauge, check vacuum. If no gauge, get to hunting. What swap did you do by the way?

[Domzz]

I went with the good ole vg30 na but I found one imported from Japan from JDM orlando for cheap so I went with it. Mine was leaking oil and either bearings or rings were going bad because there was shavings in oil. I tried to go hunting for vacuum but couldn't find anything so I might buy a gauge from advance auto parts or online and check for leakage. What is the standard vacuum?

[Trimble Epic]

The vacuum system in our NA's is actually extremely simple, there are really only a few places to check that aren't obvious.

Here's a few that you should check...

The balance tube can be a source of a leak - seems common to accidently put it back on with the wiring loom bracket under the tube instead of over it. instant leak.

Also, the balance tube has a few nipples on it that source leaks.

Another issue is that the diagram above does not include the idle air circuit, which actually sourced one of my leaks, there was an ancient hardened rubber hose that had a crack on the underside, I replaced all of those hoses with Z1 silicone and my vacuum issue was fixed.

[Domzz]

I checked all of my vacuum lines thru that diagram and I couldnt find anything. I just realized a little mistake tho. The canister line that hooks up to the left TB was actually connected to my FPR solenoid and the plenum line that is supposed to plug in the solenoid was hooked up with TB. Also had to loosen the IAVC by like 4 full rotations to get my idle up to 1000rpm again so I tried revving it and it doesn't drop below 1k as it did at all and forget about shutting off. I have yet to take it for a ride and see how it does on the road