i know this has been covered well the idle problem but it seems like every thread i read is about the idle fluxiating but mine doesn't even idle, this T2 will run like a bat out of hell if you give it gas and just move, but if you want to sit at an idle in the beginning it won't stay on for more than 3 seconds sometimes it will idle by itself but more than not, its got a rebuilt engine about 10k on it, running a racing beat turboback, FCD, HKS intake previous owner had vacuum hoses replaced during summer but that could be it im not sure looking for expert opinion but like i said it runs perfectly fine if you just get moving and don't worry about the idle at start up and warm it up by driving it around. HELP PLEASE! im only 17 i need to get this fixed!

 

For one thing, you should NEVER rev a rotary when it's cold...

As for your idle problem, try replacing your throttle position sensor...
Or like you said, it could be a loose vac line...

 

Look for the idle FAQ and troubleshoot it, EVERYTHING is covered in that thread.