2016 Prius cutting throttle under heavy load/hard acceleration

Discussion in 'Gen 4 Prius Care, Maintenance and Troubleshooting' started by RedBlueFoX, Oct 29, 2025 at 10:57 AM.

  1. RedBlueFoX

    RedBlueFoX New Member

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    Recently, my imported from the US 2016 Prius started having an issue, where under hard acceleration it would cut the throttle, above let's say 40-60 km/h. While holding the pedal down, it would stutter occasionally and halt acceleration almost completely. Releasing the throttle to a position below ~80%, the car will ride without any issues. I don't think it's a hybrid issue because the overall fuel consumption didn't change. I still average 3.0-3.5 l/100km when I'm driving alone, and it only happens at above urban driving speeds when I want to press the pedal all the way down. Accelerating at a slower rate and the car can easily do the highway speeds of 140 km/h.

    I've changed the fuel pump assembly from another 2016 Prius with higher mileage(200k miles/330k km), and the air filter to the new one, and all changes were done before the issue appeared. The issue itself appeared after I had replaced all tires with a set of new, better-performing tires. I've tried switching the MAF sensor from another Prius that drives fine, and the issue persisted. The last thing I did was I tanked at a different gas station than usual and put the fuel line cleaner product in.

    Just to add in:

    • Dr. Prius app shows the cell difference at 0.1V

    • Battery state and temperature do not affect the issue.

    • The Short Fuel Trim spikes momentarily before the throttle cutoff and then dips immediately.

    • The local dealer will most likely refuse to inspect the vehicle since it was imported from the US, and multiple local mechanics took a brief look and could not pinpoint the issue.

    • No Check Engine light present, but a lot of archived OBD codes after every scan.
      • One mechanic asked me to keep flooring it after the issue appeared, and after approximately a minute of stuttering, the Christmas tree lit up and the car shut itself down. Restarting the car cleared the Christmas tree and only left a Check Engine Light on with P3190. After clearing the code approximately a month ago, the car has kept driving without the check engine light to this day.
    • Replaced the spark plugs with original Denso plugs.
    If anyone has any ideas what could be the cause, I'd be happy to listen.
     
  2. Mendel Leisk

    Mendel Leisk MMX GEN III

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    Wouldn't hurt to ask them.
     
  3. bisco

    bisco cookie crumbler

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  4. BiomedO1

    BiomedO1 Senior Member

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    Nice write-up....
    The issue seems to be isolated to your engine (P3190) not outputting the power that's required under heavy acceleration. Could be a simple sensor or clogged exhaust pipe. That's assuming the fuel pump is keeping up with demand, injectors aren't clogged, compression is good, and air box is clean and clear of obstructions. An OEM diagnostic scan tool needs to be used to check basic functions and see if any sensors are on the borderline of failure.

    FWIW; swapping out used parts from an old car with higher miles isn't a fix, just a diagnostic tool. You don't know the condition of those parts and you've said that it came from a higher mileage car. That same part may also be defective, worn out too.....

    Just something to think about.....
     
  5. Brian1954

    Brian1954 Senior Member

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    My guess is a bad fuel pump.