GEN 1 prius P3106 powertrain code and vehicle stalls

That code is about one specific vacuum line, and it is the one that works the HCAC actuator down on the exhaust pipe. The actuator moves a flap inside the exhaust pipe and sometimes from the heat and accelerated rusting it gets stuck. This thread may be of interest.

 

Chap forgot the link, but there are many discussions of this DTC here. SYK, driving the car in the snow of MN will almost always lead to this issue. The flap and actuator rod will rust over. Another thing you should check is the fuel filler neck. They rust from snow as well and will kill the fuel pump inside the gas tank so you have to replace the entire tank. Just reach up in the rear wheel well and feel over the top of the filler tube right at the fender. The tire will throw the snow up there and it gets packed solid. Then, if it stays cold the snow rusts a hole through the tube. Later, when spring comes around, the tires will throw water up there that gets in your tank. The tube itself is easy to replace. I got some spares if you need one.

 

a couple words in post #44 are bluer than the rest

 

And that guy in 45 is colorblind, lol.

 

It can take a little while for a 1347 to appear if the weather is warm. The valve shuts to allow a cold exhaust to warm up. That happens mostly in the winter. If it's rusted in the open position and it's summer, maybe you don't get a code until winter time. If it were stuck closed, you might see some mpg decline. mostly about air pollution.