jerky acceleration

[jak219]

Does anyone have this problem? When I slow down to less than 10 mph, and then try to accelerate, the RPMs increase immediately, but there is a slight delay before the car accelerates, like the transmission isn't catching right away. When accelerating from a stop, the accelerator pedal seems sensitive, but there is no delay. And if I'm coasting faster than 10 mph, there is no delay and jerkiness when I press the accelerator.My car has done this for as long as I can remember, but it is still annoying.Using the highest octane gas hasn't helped.2008 automatic. THanks.

[kostby]

Have you tried scanning it for free at your local auto parts store? You didn't mention if you ever got a Check Engine Light or not.Although it sounds on the surface like a transmission problem, I'd suspect an air leak or a vacuum leak somewhere in the intake system.I had a similar acceleration problem with a manual transmission Escort. Turns out that the rubber/plastic intake runner had a tear in the bottom side of it where it wasn't visible. Upon acceleration off idle, the tear would open up and lean out the fuel mixture. The computer would detect a lean condition and richen the mixture, and probably do something with the timing too.Then the engine would almost stall, because the mixture was too rich. The RPM would drop, the tear would close, letting in less air, and the cycle would repeat itself, over and over, until you got up to a constant speed of about 20. At that point, either the tear was open all the time, or the RPM was high enough that it didn't matter.The car was almost undriveable in really cold weather. Of course, in San Diego, you'd never find out about a cold-weather condition!

[Water boy]

Or is it the "drive-by-wire" (DBW) issue?At off-idle the throttle response is very jerky.Didn't I see (read) somewhere that you can reset the DBW to get better smoothness?

[rollavvti06]

have you changed your spark plugs they can do that too have have had that happen when i put in cheap plugs

[star_deceiver]

Run some injector cleaner through it.

[RIT]

Is it downshifting, and then accelerating from the lower gear ? Sounds like a normal slushbox's operation.

[bryan59]

Well .... I can attest to this trait. We seemed to be plagued by that STB 09-07-30-010But this hasn't done it since we've reached 3000Km or so.Had the dealer do that PCM reprogram but don't really notice any difference.This isn't something thats just happened either its been problematical since we bought it new in June ... a GT by the way

[vintagegz]

I think he is referring to the dead spot when you have had your foot off the gas pedal at lower speeds and then try to accelerate smoothly/slowly, there is nothing there until wham! it downshifts and away you go. My 09 with the 2.4 auto does this as well. The TSB is for clunking when coming to a stop. I find it aggravating that at 5000kms the gas pedal is too touchy when you want to accelerate from a stop, you would think the calibration could be changed slightly but with Pontiac gone there will be very little incentive to do this.

[dragon64]

Quote, originally posted by vintagegz »I think he is referring to the dead spot when you have had your foot off the gas pedal at lower speeds and then try to accelerate smoothly/slowly, there is nothing there until wham! it downshifts and away you go. My 09 with the 2.4 auto does this as well. The TSB is for clunking when coming to a stop. I find it aggravating that at 5000kms the gas pedal is too touchy when you want to accelerate from a stop, you would think the calibration could be changed slightly but with Pontiac gone there will be very little incentive to do this.What you are describing is Drive By Wire throttle lag. With an old mechanical throttle linkage the action between the input of your foot and and the opening and closing of the throttle plate was linear. With DBW the signal received by the throttle body actuator from your foot might only be 60% of the actual pedal movement. All the 09+ Toyota products seem to have much greater DBW lag that other car manufacters and models with an auto have approx. 5% greater lag than the same car with a manual gearbox. The attached graph will give you a better idea what I talking about when you compare the black and blue line.

Attached files

[jak219]

Yes vintagegz, that is it exactly. There is nothing there, and then wham! And then when accelerating from a stop, the pedal is too touchy.Dragon64, are the axes of your graph pedal displacement and engine rpms? Or is the horizontal axis time? I'm wondering if it is a DBW lag issue if the engine is responding immediately but there is a time lag before the transmission engages.

[KNINE]

Mmmmmmmmmm. Jerky.

[ParknVibe]

Your graph speaks for itself. It shows exactly what my problem is with my '09 Vibe with 2.4L and the 5 speed auto trans. My car acts like the blue plot line shows taking off from a stop. I must maintain a light foot to prevent a jerky and zoom take off. I talked about this problem a number of times within this forum during the past year and one half. When I first took a test drive of the Vibe at the dealer, I almost got wip-lash.

[bryan59]

I have this drive ability issue too but the 010A TSB had no effect on this part though the car did feel a little different from before.We went the CAMVAP route .. primarily for the hard down shifting issue which unfortunately cleared itself just before the hearing, grrr ...A GM rep drove our car and declared that it was normal .... he drove it so slowly and gradually that it was no wonder he came to that conclusion. I drove his own non GT auto 2.4l .... and while still in the parking lot I could tell the difference between them!! I don't know if his would be a DBW but it was a 2009?So has anyone had this issue go away after more accumulated mileage?Or done anything like modding the intake for a few more HP to help with this?Hey dragon64 where did that modified DBW (red) come from and is it possible to get it done?I suspect this is going to make winter driving much more difficult!

[lolobug22]

I have this issue. Only in cold weather, below 40, and only the first mile I drive in the morning. Fine the rest of the day and all summer. Recently had my PCM replaced but that didn't help either. Taking it back into the shop.....this has been going on with my car for almost three years!

[dragon64]

Quote, originally posted by bryan59 »A GM rep drove our car and declared that it was normal .... he drove it so slowly and gradually that it was no wonder he came to that conclusion. I drove his own non GT auto 2.4l .... and while still in the parking lot I could tell the difference between them!! I don't know if his would be a DBW but it was a 2009?It would have DBW. Even the previous generation of Vibe/Matrix was DBW but lag was as much of an issue as it is in the '09-'10. Lag was much less in the '08 and earlier Vibe/Matrix but the hardware is not swapable with the new models before you ask. Quote »Hey dragon64 where did that modified DBW (red) come from and is it possible to get it done?I suspect this is going to make winter driving much more difficult!The red line on the graph is my own '09 1.8 manual. It's one of those thing about working in product developement in the aftermarket industry everybody personal cars get used as test mules even for products that will never go to market. bacisally its a "black box" that intecepts and modifes the signal between the foot control and the servo on the T/B. At this point it is only a test of concept with no plans to market it. In the winter it should actually improve driveability. One of the big problems especially with a manual is the lag in the first 30-40% pedal travel. Revs either lag behind the speed for the gear causing the engine bog or stall or over rev spinning the wheels which engages the traction control causing a lurch of accelleration and or sudden lose of forward motion.After working with the Toyota tech reps for another issue altogether I got the impression that in the '09-'10 Vibe some of the jerky accelleration and/or decelleration many complain about is an interaction between the DBW throttle lag and stardard equipment T/C & ESC systems. From the original issue we found out that Toyota's ESC parameters are very sensitive to the point were some of their models are effected by down sizing wheel size and increasing tire sidewall ratio triggered the sensor into thinking there was too much body roll. From tests on my own car I also believe that engine mounts are too soft as well. Upon accelleration or compression braking the whole drivetrain seems to have a lot of movement which spoofs the T/C system into engaging the front brakes to control non-existant wheel slip. I just fabbed up the parts for a adjustable hydraulic engine damper and still aquirying data as to how much effect this has.For those that asked about the Parameters of the graphs. The vertical is I/O voltage and the horizontal is time lag between the signal generated at the pedal and input at the T/B actuator.

[bryan59]

Quote, originally posted by dragon64 » or stall or over rev spinning the wheels which engages the traction control causing a lurch of accelleration Hmmm..... pretty much describes what my wife complains about! I will have to try turning off traction control when starting outQuote, originally posted by dragon64 »From the original issue we found out that Toyota's ESC parameters are very sensitive to the point were some of their models are effected by down sizing wheel size and increasing tire sidewall ratio triggered the sensor into thinking there was too much body roll. From tests on my own car I also believe that engine mounts are too soft as well. Upon accelleration or compression braking the whole drivetrain seems to have a lot of movement which spoofs the T/C system into engaging the front brakes to control non-existant wheel slip. I just fabbed up the parts for a adjustable hydraulic engine damper and still aquirying data as to how much effect this has. The only thing i've noticed from downsizing to my 16" rims with snow tires, 205/60, is some more side to side body roll otherwise it pretty much drives the same

[MajorAD]

Dont feel bad ,my 2010 2.4l Vibe does the same thing,kinda annoying because it feels like its also wasting gas.My 2.0l, more than 10yr old Rav4has better "response" than this vibe,you figure that Toy Eng would have solved this by now.

[aizhol]

I have exactly the same problem. Accelerator pedal does not respond for some time and then accelerates sharply.I live in Kazakhstan. -20 C cold is usual thing here, it gets to -40 and even -50 sometimes.I bought Vibe 2wd automatic few months ago. It has 70000 mileage and now I have Check Engine light on as well.Is there any solution?

[bryan59]

SO .... does this latest Toyota recall have any bearing on these issues?I can't say that the gas pedal feels sticky to me but ....

[bryan59]

Just heard on the news that the Secretary of Transportation, Ray Lahood, is looking into this Toyota pedal fix but he also mentioned looking into the electronic side of the issues. This could be helpful in what we're all saying here about the drive ability issues with the Vibe

[bryan59]

So ... we've had the Toyota gas pedal fix done to our Vibe.I wasn't expecting there to be any difference ..... but ..... there was!Off the line and otherwise it feels like a normal car now not that there still doesn't appear to be dead spots with the auto tranny where it will lag but its much smoother now and predictable.Has anyone else had the repair done and did you notice any difference if you had these problems?

[redhotmetallic]

My 2009 2.4L Vibe has been perfect up to this point, but I just got the repair/fix! done to my Vibe gas pedal and now i have the problem of the jerky acceleration. It's driving me nuts! i've been to the dealer twice and they assure me it's fine.They too test drove it and found nothing wrong. I asked about the TSB for the upshift problem and they told me it was done as part of the pedal fix. My wife does most of the driving and at this point I don't know what to do. She actually want's to get rid of it as fast as possible!

[star_deceiver]

I'm assuming that you have and automatic. Do you drive it usually in drive or in the 'manual' mode?

[redhotmetallic]

It does it in drive mode, haven't really tried it in manual mode.The thing that gets me is it was great befor the "fix" of the gas pedal. My wife doesn't feel safe driving it now. UGH!!

[redhotmetallic]

I drove the car today,seemed pretty good.I tend to drive the car harder than my wife and the gas pedal see's the floor alot!! I think it doesn't like when you drive it normal!Does anybody know if the car/trans "learns" your driving habits and adjusts accordingly? If that's the case, then this car gets two very different driving habits to learn.I wonder if that's the jerkyness we get sometimes...

[star_deceiver]

Yes the car "learns" the way you drive so it wouldn't surprise me that it wants to be driven hard.If you disconnect the negative battery terminal for about 5 minutes you can reset the system. Then drive it nicely/gently for a few days and see what happens.

[ponta2147]

Quote, originally posted by star_deceiver »...it wants to be driven hard.Sounds dirty.

[star_deceiver]

Quote, originally posted by ponta2147 »Sounds dirty. Quote, originally posted by star_deceiver »Once the car learns to respond to being driven hard......learning how to drive stick!!! Now that innapropriate thinking has been delt with ...we're back on-topic....