She's acting up....

Premo34WV

So I'm driving a bit aggresively and as I downshift from 4th to 3rth and allow the car to coast, the synchro rev perfectly matched 3rd gear revs and I let out of clutch, then something happened....

Instead of engine breaking the car maintains speed or even very slightly accelerates.(on its own with my feet completely off of all pedals) Once I apply break pressure it stops doing this. No the accelerator wasn't stuck I was curious so I tried to duplicate the action and once again the same thing. This time I put my foot behind the pedal and tried to pull out, it wasn't stuck. It only happened at right about the 4k rpm range and for only about 3 seconds.
The action felt like something was up with the Synchro system, like it was trying to bump the rpms while i was in gear

This happened about an hour ago and is definitely cause for concern. Anybody ever heard of this happening?

dszombiex

Well, not quite the same but related to the synchro rev...

I have the 7AT. I was under the impression that the synchro rev is only on when the tranny is in sport mode for the auto and I manually downshift. Until a few days ago this has always been the case for me.

Well this past weekend when I was coasting downhill in full auto mode with my foot completely off the throttle, the car suddenly revved twice! It was a decent rev too like up to 4k or something. I drive in full auto mode when I'm lazy or during my daily commute to work all the time. Its never gone off in full auto mode before.

speedworks

I've had this happen many times with spirited on/off ramp driving. The car does feel like it accelerates, but I think it is only not braking (by the engine). I am not sure what or why the car does this - but it has done it since I have had it (Jan). It is only noticeable when I am at/near the limits in a turn (at no throttle).

noodles

i have heard of this before and more then likely what causes it is the that the rev match is designed so that when you downshift your going to be right back on the gas so it anticipates this and does it for you.

Nikon FM

Same thing has happened to me (many times) while working through back road twisties. I'm just calling it a feature

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shabarivas

Maybe the VVEL was throwing the ECU off.. interesting... lol my downshifts rarely end up near 4k

speedworks

Had to bring this back alive. After driving this car for over a year, I notice it a lot more, and have the ability to recreate it. Anytime I am on a long on/off ramp from a highway, and have a good speed going, and lift off the gas (to hopefully let the car decelerate), the car maintains the speed. Being close to the edge of comfort, it does make me a little nervous, as it is close to the edge of a slipping (and I am prepared to countersteer). So there are 2 inputs, good amount of steering input, and g-forces - it is either condition (or a combo of them) that creates this problem. Anyone else out there have this issue and have you had more time to diagnose it? I am at the point now that I am going to test it around my dealership, so that when I take it in (in the next week or 2) I can show them. I would suspect those that do DEs would feel this (if it was common), on long sweeping turns (which is the only time I feel it). I also notice that it will start to decelerate once the long sweeping turn straightens out (less g force and steering input), or I slightly touch the brakes. It's actually much easier to recognize it since I have installed the FI exhaust as you don't get the decel gurgle until it goes away.

Any others? After all of these Toyota issues, I wonder if Nissan has something similar; these electronic gas pedals concern me.

Pharmacist

I read that porsche has a feature called engine torque drag control or something like that as part of the porsche stability management program. What it does apparently is that it opens the throttle a bit so that the engine revving down doesn't rev down too quickly and cause too much drag on the rear wheels and break their traction and lead to spinning out. Perhaps the Z stability control has a similar feature?

speedworks

What I am having happen is definately not a 'wanted' feature. And it doesn't rev down at all (maintains rpm), until either the turn increases radius (less g force) or I touch the brakes. Thanks though.

onekneedown

Why would you expect the car to significantly slow down just by lifting off the gas, especially if you are going at speed into a turn?

speedworks

I don't expect it to significantly slow down, but I do expect it, due to friction, to not maintain speed, as anyone should. Cars won't maintain speed, if you don't have an input like fuel.

Zeto

Very interesting. I have come across the same thing and thought it was just a placebo effect but it's just as speed works has described.

speedworks

Yeah, you won't notice it, unless you are daring enough/experienced enough to take a turn at a significant speed. On a racetrack, I would feel this constanty. I scare my passengers every time I do it, but the issue I feel, scares me sometimes, and it isn't what a car is supposed to do.

bloodo

I think this is calls momentum. Unless you guys shift it to a very low gear, where the rpm needs to maintain the same speed is significantly more, then you will likely not see engine breaking just by lifting off the pedal. Example: just accelerate, downhill, level pavement, etc.

As speedworks described, he takes a turn at a significant speed, that speed will maintain because of the angular momentum. Not sure what gear he is normally in, but if taking a sharp turn at like 4th or 5th gear going 65mph, simply lifting of the gas pedal will not slow the car down because the rpm needs to maintain the speed is still low. This is just an example.

speedworks

Its not momentum, trust me, I have lots of experience at speed (on a track), and know how a car should feel/act in turns. The problem my car has, and I can assume others as well have, is that the car maintains a throttle in these situations. Its not normal, and hopefully I will be able to recreate it with a tech in the car. It does it for seconds in a long sweeping turn, so there is enough time for the car to slow (and when I say slow, I mean 1mph), you can hear the throttle (through the exhaust note not changing), until the situation changes (brakes or straightening) and then it releases the throttle. My guess is something with the g forces are causing a sensor to change.