420A Engine turns off

[Lsjuice]

I have a 95 gs 2.0, I recently reinstalled the engine I installed new gaskets, fixed the engine head, etc. Turns on nice but it suddenly turns off, not always tho. I’m thinking a vacuum leak? Or the IAC valve maybe? I don’t know a lot so I would really appreciate some help to help me diagnose it.

 

[BLACK'98DSM]

How does it act before dying? Idling high, low?...

 

[Lsjuice]

How does it act before dying? Idling high, low?...

Sometimes it idles a bit high, but really most of the time it’s idling normal, then it starts idling low and just stalls