2017 Prius - Gen 4 acceleration issues - type two

make sure the hybrid battery vent is open and the filter clean. might be worth checkin/cleaning the blower.
was it parked in the sun?

 

Although not mentioned there is a filter behind that vent too.

 

A Prius does not have a torque converter or gears like a traditional auto transmission does, so it cannot "slip". Of course, problems can arise in the drive train that make it seem like that is happening, but probably they cannot be rectified by changing the transmission fluid. There is no harm in changing the transmission fluid, and some owners believe it should be done regularly, but Toyota does not require it as they consider it a "lifetime" fluid.

Did you happen to notice your HV battery's State of Charge as displayed on the MFD when the event you described was occurring? If it was at a very low level, that could explain the revving of the engine and the car's overall sluggishness.

In any event, the HV components of your car are still under warranty, so if this issue becomes serious enough that an error message or lights are displayed on your dash, you should be able to take the car into a dealer and have it analyzed and, if necessary, repaired free of charge.

 

Another thing that can happen: right after starting, the Prius computer likes to baby the engine, and use mostly battery power to get you going down the road, with the engine more or less idling. As the engine warms up, the computer gradually puts it more and more into the mix; usually you don't notice that. That's why there's generally no need to wait around "warming up the engine" before driving, as people used to do; the computer is taking care of that, even while you're already moving down the road.

But if you're driving along in that early stage and you happen to press a little harder on the go pedal than the available battery power can cover, then the computer says "ok, so much for babying, gonna need engine for that" and the engine will kind of abruptly rev higher to give you the additional power. If you're not used to a Prius, that can feel/sound like "slipping", but it's perfectly normal.

 

You are assuming it is not a high mileage vehicle. If there are too many miles on it it is out of HV warranty.

 

How long have you had it and is the VSC light activating? Japanese cars are extremely aggressive with "traction control," especially from a dead stop. Especially the "Prius," It will cut power and shut the motor down! Wait and then say OK, if you let off the throttle and then accelerate as "expected." A gentle touch on the accelerator is required.

Just a thought.

 

Yes, with a low SOC on the traction battery, the result is like trying to launch a manual transmission car from a stop in top gear. A lot of engine noise and no "go" In fact, the Prius ICE is always in "top gear" and the Power Split Device (PSD) feeds in torque from the electric motor(s) to assist in getting the car moving. Assuming there is sufficient traction battery power available, of course.

 

The Prius never uses ICE for propulsion in reverse. It is always battery only, so that's why it felt normal.

Are you sure the parking brake was not engaged, even partially?