Low idle until warm, then stumbles
 

I have got my 951 running, but when I cold start her, she will idle at 400-500, until she warms up. But when she is warm, and i rev the car when warm, she will dip back down to 400-500 and stay there, until it warms up. She will also do this on a warm start, right after she warms up and i shut her off, then start her right back up. She has all new vacuum lines, but maybe one or two isn't tight enough? I don't hear a vacuum leak, but thats not a true test, I know.

Not sure if they are the same as the non turbo but you're idle control valve for the ca maybe stuck open. ( aux air valve)

Coolant sensor, O2 sensor and AFM are important when you get warmed up and into closed-loop also.

I'd suggest starting with the DME temp sensor under the front of the intake manifold (blue connector) It could also be the connector is loose or not making connection. Get a copy of the DME connector pin assignments and see if the readings from the sensor are reaching the connector.