2018 Prius Sputtering and Smoking after sitting in 0 degrees

Hey guys long time lurker but need some help. 2018 Prius, ~78k miles. Has always ran great, all highway. Drove it yesterday no issues. It sat outside in almost 0 degree weather. Started it up today, had a rough idle. I'm used to that when it's really cold in the 2012 Prius. But rough idle didn't go away. The ICE actually died after a minute of trouble idling and had to restart the car. Started seeing some white smoke from engine bay and still rough idle.

Figured blistering cold didn't help so I backed it into the garage. Sputtered it's way in. After some troubleshooting, it does it right way, runs rough. A few seconds after running, white "smoke" is seen coming from behind the engine. I don't think it's actually smoke, it dissipates really quick and has a heavy gas odor. None of these issues were seen last night so guessing something rubber or plastic cracked, fuel line? Nothing on the ground either fluids wise.

I tried peeking back there by the firewall but can't see anything. In the process of warming up the garage and going to take the windshield lower cowl off so I can see back of the engine better. That or jack it up and look underneath.

I need to figure out how to scan for codes. Torque found nothing. Using OBDLink LX adapter and dedicated android device.

Does anyone have any freaking ideas what it could be? Seriously hoping nothing major. I had a 2012 Prius go 235k miles with 0 major issues, got rid of it fully functional.

 

Thanks for the replies! 0 Fahrenheit and I think we might have just dipped into the negatives. I let it run for a bit, scanning w/ Torque, nothing. Nothing on dash either, just idled like garbage and sounded like it had an exhaust leak like an old beater car with a small leak. Engine would borderline stall when hitting the gas. The smoke/vapor went away after idling for a bit so thinking exhaust fumes leaking somehow, plus it's cold so they should be very visible. I remember seeing either ICU or ICE? unavailable, on dash once. Didn't snap a pic tho and didn't leave a code but the engine still ran.

After running for a few, I shut it off, ran back inside to get my phone to take some more videos and it started up just fine! ¯\_(ツ)_/¯. Took it around the block and she's back to her old chipper self. Absolutely no idea. Best theory is the EGR valve was stuck open but you would think it could have thrown a code. EGR would explain the smoke, if it were dumping exhaust back into the engine and it found a way out behind the engine. Would also smell bad like gas fumes, sucking in fresh exhaust to the intake and combusting them. But same deal tho, the O2 sensors should have been freaking out but I doubt it was running in closed loop. Don't know how the Prius works but I know most cars run in open loop when cold so it ignores most of the sensor and runs off programming until warm. I have 100% no idea just glad nothing major.

 

That makes some sense, injector stuck open, flooding a cylinder. Explains the fumes and smell. Something must have gotten stuck from the cold because it's fine now. In Texas, I really doubt we have fuel/anti-freezing gas additives like up north for winter, we're hitting record lows for decades worth of low temps. Little bit of water in the gas maybe.

 

Smelled like gas/exhaust. It didn't linger either like smoke and it would only do it with the engine running. The second you shut it off, the smoke/mist would instantly dissipate and a few seconds after starting, it would appear.

It's been running for a few hours now, running as in it's on/ready. I have a AC/DC inverter hooked up to it powering our WiFi and living room TV/lights because of the rolling blackouts so the engine cuts on and off when it needs to. Issue hasn't reappeared.