2017 low miles startup rattle

Drive it everyday for a couple of weeks. See if the behavior repeats and if it smooths out quickly.

Have a borescope test first. I would wonder if the miles are legitimate.

Don’t waste money on plugs, coils or injectors if it runs smooth the rest of the day or only does it twice a month.


Car Care Nut HG Borescope at 7:40

Shudder video

 

maybe just a one off? did you start it the previous time and shut it off before it finished warmup?
i can't think of anything else that could cause that at 20k. iirc, mileage can be faked. what's the history of the car?

 

that is a very common cause of shaking on the next start. unburned hydrocarnons left in the manifold or somesuch

 

You need to drive it every day and start stop a few times after the first drive of the day to see if it repeats. If it repeats, a diagnosis and repair can save the engine.

 

That's ultra-low miles. Could be @ChapmanF's "slurp" of moisture from the intake trick, but other'n that I can't see it being head gasket failure, yet.

2017 Prius v is still "third gen", with all those foibles.

 

I had that happen once. Moved the car from driveway to street, and then back sometime later, so the engine only ran for a few seconds each time. Next time I started it it shook something terrible. Now if I'm moving the car like that, I'll let it run for a minute or so. Hasn't happened again since as a result. Scared the crap out of me because the engine shake was pretty fierce.

 

You shouldn't shut off the car after moving it 5 feet. In your high humidity climate, it's best to let the ECU turn-off the engine - then shut it down. This way you bake-off fuel and moisture trapped inside your engine. The car should be driven at least on a weekly basis to get everything lubed up and contaminates baked-off. This also keeps the fuel from taking on too much moisture and going stale.

Just my opinion - take it of leave it......

 

I can't take credit (or blame, or whatever) for the information we got from Kore971, who foreshadowed, and then announced, the TSB about it.

Exhaust contains a lot of water (that and CO₂ are the biggies), and it seems when the engine hasn't warmed up much, some can be left as liquid in the small-bore EGR passages in the manifold. Those lie barely an inch below the intake ports, so it's no trick for that bit of liquid to get snorted into the intakes when the engine cranks up and makes vacuum.