Firm jerk in car

[perryma]

I have seen posts on this before but my car really has a strong jerk in it at times. I notice it most when I slow down but not to a complete stop and then speed up again. I think it is the gas engine kicking in from being all electric but am not sure. It does it sitting still sometimes to but quite as hard. If it were any other car I would say the transmission was going out (I have had that before). What could this be?

[pewd]

most likely its the internal combustion engine (ICE) shutting down.

[NoMoShocks]

Lucky for you your car has a firm jerk. Mine has a flabby jerk.

Oh sorry, I thought you were talking about the driver.

But seriously, is the road at all wet, and have you ever noticed if the yellow VCS light flashes on the dash? The stock tires have realy bad traction, and the wheels can slip on anything as slippery as a patched pot hole.

I find the transitions from Gas Engine on and off to be remarkibly smooth, transmitting more vibration through the frame than to the drive train.

[patsparks]

You pinched my joke, I was going to say just drop the boss home and stop complaining but I won't now.

[firepa63]

When cold, the ICE tends to shudder more than when it's fully warmed up. Maybe your jerk is really a shudder.

[john1701a]

Originally Posted by NoMoShocks

I find the transitions from Gas Engine on and off to be remarkibly smooth...

So do I, but that's only after the initial break-in was complete. It smoothens out over time.

Given the right temperature conditions though, you can still catch a thump from the engine shutting off. But most of the time, it's undetectable other than from watching the ScanGuageII to see the RPM drop to zero.
.

[Ichabod]

Well I was going to make a much less savory joke, but I'll refrain

To really diagnose your mystery "jerk" we might need more information... but it does sound like you're talking about the regular behavior of the car. The engine feels like it sputters to a stop sometimes... If you turn off radio, a/c and anything else that makes noise, you can hear if the engine stops when you feel that shudder. It's usually more noticeable one time during a given drive, and after that first time, the engine starts and stops more smoothly. There's a technical explanation for that... that I don't know off the top of my head. But it's not damaging to the car.

The transmission in your Prius is pretty different from that of any car you've had before, and not as likely to "go out" because it's much simpler and more robust than other types of transmissions. No clutch, no shifting of gears.

[cyberprius]

Thanks so much for this post....and I only opened it on a WHIM

I've been worried about my Prius because I have noticed this jerk/shudder a couple of times, both times when the temperature has been in the 30s and the car was cold and my car has around 600 miles.

I thought the only jerk in the car was my husband, who managed to smash it up at 400 miles, but now I see I have a second one to contend with, but at least it sounds like a somewhat "normal" thing.

[donee]

Hi Cyberprius,

I think what is going on is that as you slow down the car is gearing itself for max regeneration gearing, and reving MG1 in reverse. When you go to accellerate, MG1 must slow to a stop (from as much as 6K RPM) and reverse. Its that rapid change in RPM that is making the shudder and also conversts the transmission to a high ratio so the engine can rev up to high power. If you pause a little bit during the depression of the accellearte until you feel a small shudder, then go for full desired acceleration the sudder will be much less.

[Tideland Prius]

Given that it's an 05, I'll wager it happens when the OAT is low (say below 5°C/41°F)