The vehicle is experiencing juddering or jerking during acceleration.

[Squirrrel]

Greetings,

I own a 2016 Toyota Prius, Generation 4 (UK model). It has accumulated over 300,000 kilometres, having mostly served as an Uber/taxi during its lifespan.

Nonetheless, do not allow this to astonish you, as it is likely one of the most meticulously cared for and well-maintained Priuses around. Operates as if it had only travelled 60,000 km (under optimal conditions). Consistently operated judiciously and never mistreated. No costs were withheld.

It has lasted 2-3 weeks, and I have seen persistent juddering or jerking during acceleration. It resembles a malfunctioning sensation. The engine seems to be vibrating. This occurs just during acceleration and while engaging the gas pedal. In EV Mode or Hybrid mode, the juddering ceases, and the vehicle glides smoothly as expected. However, upon acceleration and engine engagement, the whole vehicle experiences juddering and jerking. This occurs from 0 mph to a maximum of 50 mph.

I have completed the following tasks:

    I first replaced all four spark plugs with genuine Toyota spark plugs, which is my customary practice. My previous ones were still functional and had considerable longevity, however I proceeded to replace them—no difference ensued!
    I subsequently changed all four ignition coils, with only genuine Toyota components, although there was no discernible improvement.
    I put genuine Toyota Fuel Treatment into my fuel tank - no effect!

Additional contextual information:

    There are no EML or any other warning lights illuminated on the dashboard at any time, even during instances of juddering and jerking; nothing has been shown so far.
    The oil and water levels are satisfactory, and there are no leaks or losses of either substance.
    My fuel usage is same; there has been no adverse impact in that regard.

The vehicle is well cared after and maintained. Maintained every 10,000 to 12,000 miles with only premium components from Toyota. The engine operates on Castrol oil, since it is the best product available and offers extended longevity.
The vehicle has only used Shell petrol and would never employ any other fuel.

Kindly provide assistance; do you have any recommendations on the potential issue?

[FreexPatty]

It may be attributable to several factors.
Given that mileage, the gearbox may be experiencing slippage.
Alternatively, an issue may be emerging inside the high-voltage battery pack.
A fractured motor mount.
Or water has collected in the fuel pipes.
Or oil collecting in the intake manifold due to the PCV system.

I recommend that you have a hybrid shop examine it.

[Squirrrel]

Thank you for your response and recommendations.

In response to your inquiry, my car has exceeded 300,000 miles (not km).

I connected it to a diagnostic machine (Snap-on), and it displayed the following problem code:

P2681-72 Engine Coolant Bypass Valve Actuator is in a permanently open position.

Please note that there are no EML lights visible on the automobile dashboard; hence, this is a code detected by the diagnostic system that is not clearly shown.

We inspected the EGR valve, which was completely dry and impeccably clean, devoid of any dirt or oil, and showed no signs of obstruction whatsoever.

Are there any more recommendations?

Thank you.

[Squirrrel]

[Squirrrel]

[FreexPatty]

Given the mileage over 300,000, it seems the cooling system has been significantly neglected, and it is probable that the whole system is rife with rust, similar to the valve that was replaced. It is probable that some of the minor passageways inside the radiator are already obstructed.

It is prudent to consider your course of action when it encounters an issue beyond your ability to resolve, since that moment may arrive imminently.