Lexus Gs 450H 4gen random juddering, jerking or stuttering..

[Zizan]

Hi all,

The car has 55k miles with original service history to Lexus registred first in 2017 .I drives great but any once in the while after driving the car fast on the highway for longer periods before coming to a stop with or without the foot on the brake the cars starts to juddering, jerking or stuttering.The brakes are ok (checked at the dealer), dealer says it may be bad fuel , but the feeling is something betwen engine stalling and rapidly abs engaging.This happened a few times only after highway driving right before the EV mode enters either during braking or coasting.Pressing the acceleration pedal once seems to cure the hiccups.

English is not my first language so please bear with me.

[stripester]

I have exactly the same problem... Don't know why no fault codes... Watching this thread now... 

[diegolis]

Hi guys, same here…

first time was just after replacing the tires so I thought it was the new tires messing with the abs. It happened just once more and yesterday again but just briefly. So far it happened when slowing down on the highway for the toll, gentle down hill and light braking from 120kph. Its quite violent when it happens. As I understand it, If the engine misfires it shouldn’t make the car shake like that as there is no hard gear engaged so I suspect abs, the transmission or a software glitch that doesn’t quite work out how to downshift from the high gear to the low one when on a gentle braking. Just my 2 cents worth of guessing.
Hoping more versed people read this and shed some light on this issue.

[Steven Lockey]

If it was misfires, you'd 100% have error codes. 

[cruisermark]

Hi

The Mark 3 LS400 suffers from a very similar fault which is down to dirty throttle body - could the same issue apply here - or is engine not running at that point?

[diegolis]

Hi, thanks for the replies.

Can’t say 100% whether the ICE was running due to the startle effect of the shaking but I would say it was on as I don’t remember seeing the EV lcoming up. The shaking started at a speed where the car normally transitions to EV (when all conditions are met) but so far it was only when slowing down from highway speeds with the ICE idling and super light braking. When the Battery is full I know the ICE is not being shutdown to protect the Battery. It’s dawning on me that when slowing down from high speeds with light braking the rate of charge is so high that it goes into protection mode (full battery) at the same time it was sending the signal to shut the ICE down.

With the dirty throttle body does this happen all the time or is it also random?

thanks!

[cruisermark]

With the dirty throttle body it only happens when slowing down from speed e.g leaving the motorway and slowing down - engine turns off !! so you could be doing 50/60 mph with no power steering😨

[diegolis]

Being in that position would be a bit unnerving!

I dont believe that’s the case here, I am more inclined towards either the shifting between the two gears and/or the transitioning to EV but could be anything 🙈

[stripester]

I have the same issue, I'm following this thread and will try to log some data if possible... 

[diegolis]

Let’s see if we can come up with something!
What kind of brakes do you have guys, the bigger brembo with floating rotors or the “normal” ones?

I have the brembos 🤓