M42 engine won't stay running after rebuild

[CFeld]

After putting my engine back in my 1991 bmw 318i I can start it and if I give it some gas it will stay running. If I do not it will drop down to about 750rpm and then die. I do not have the exhaust hooked up (which has the o2 censor) could that be the issue? Thanks

[Car Addict]

Double check for vacuum leaks. when i rebuilt mine i didn't see a hose had gotten a small cut upon installation. fixed that and was good to go.

[CFeld]

Does anyone have a diagram of how they should be assembled.

[iPee]

How what should be assembled?

[Gerta]

OP - Search "Mess Under Intake". If that is what you are referring to.

[CFeld]

https://www.youtube.com/watch?v=kW7QcfKPdto
This is after 3 or 4 minutes of keeping it reved from 1.5k-2k. Whats wrong with the temp gauge and why does it take so long to idle?