Brief shimmy/sway/wobble when I press/let off accelerator

[rentarider]

I've got a 99 4runner Limited. There is a bit of a shimmy or sway whenever I push or let off the accelerator. It is generally only noticable over 30 mph and gets worse as the speed increases. (It can be fairly violent at high speeds...) It doesn't do it if there changes in the level of acceleration, only if I completely let off the accelerator or go from coasting to accelerating.

I checked the bushings on my steering rack and they were a bit worn so I replaced them. The steering is tighter but the shimmy/sway/wobble still persists when I press or let off the accelerator. Any help would be appreciated...

 

[shootmymime]

does the car shake? (drive line) or does the steering wheel shake? (alignment)

 

[rentarider]

The steering wheel isn't really affected. The car doesn't shake either. It is more the car takes a bit of a dive towards one side or the other and gets some sway from that...

It is almost as if pressing and releasing the accelerator change the alignment, or direction of the tires slightly...

 

[shootmymime]

ok when you hit a bump, how many times does the continue to bounce?

 

[rentarider]

Doesn't seem to be a lot of excess bounce...Is there a good way to test the struts? I'll try to pay closer attention on my next drive to make sure.

 

[roark4runner]

could it be the u-joints?

 

[rentarider]

Just noticed, I made a typo. It is actually a 98 4runner...shouldn't change anything though...

 

[shootmymime]

u-joints will make noise and shake a car (like a rumble) when accelerating and deceleration, but he says the car pulls one direction while accelerating or decelerating, are there any knocking noises or grinding noises coming from the car?


how many miles are on the struts? they should be replaced ever 60-80K miles, i did mine at 200,000 because i almost lost control on the highway (i am not saying you problem is 100% struts at this point)

a good way to test u joints it to crawl under the car and grab a hold of the driveshaft and rotate it one direction and the back to the other, if there is any slack or if it rotates the ujoint bushings need to be replaced

 

[Kmvreter]

...Is there a good way to test the struts? ...

Push down on a corner of the bumper and get the truck cycling in a vertical motion. You should have to press it down on each cycle and it shouldn't rebound more than one complete cycle. Do this at each corner. If one strut/shock is bad it will stand out from the others. Also, do the same to a buddy's truck or at a stealership to compare it to a newer truck.

Is it possibly an engine mount? Not sure how to diagnose that.

 

[rentarider]

Thanks, I'll try some of that this afternoon and see what I come up with...

 

[shootmymime]

i talked to my boss, he said it is not in the drive line but rather the suspention, try checking the rear suspention bushing such as idler arm, control arm bushings, and in the front check tie rod ends, ball joints.

 

[Link12]

Thread revived. My 2002 does this exact thing. I think it is the spring and shocks are just very worn out. I have a toytec ultimate lift on the way and I hope it fixes the problem. I can put my knee on the back bumper and bottom it out really easy.

 

[Link12]

Anybody else ever had this issue?

 

[Jswaguilar]

Reviving the thread! My 96 limited does this same exact thing. The best way I could explain it is like the OP said, given an example I'm coasting at a speed of around 30mph or more and I give it gas, it's as if only 1 wheel responds. Which would allow it to pull left or right instead of straight. I can press and release the accelerator several times in a row and the "swaying" increases.

 

[mtbtim]

Reviving the thread! My 96 limited does this same exact thing. The best way I could explain it is like the OP said, given an example I'm coasting at a speed of around 30mph or more and I give it gas, it's as if only 1 wheel responds. Which would allow it to pull left or right instead of straight. I can press and release the accelerator several times in a row and the "swaying" increases.

I would check your front control arm bushings and your rear control arm bushings. I'd also check your front differential support arm bushings. I'm sort of betting on the rear control arm bushings because the rear wheels are getting the power when you give it more throttle. The rear axle might be unstable due to the worn upper and lower control arm bushing causing a sway in the rear end.

 

[deves2]

its the rear control arm bushings.....I just replaced mine a few weeks ago due to the same issues you are having. FIXED

 

[jross20]

Sounds like broken upper rear control arms, but I could be mistaken. Something is causing the axle to move.

 

[St Runner]

If it sways and dives during braking too then I would say the from lower control arm bushings. If braking does not effect it then I would agree on the rear control arm bushings being the problem

 

[Bad Luck]

Reviving the thread! My 96 limited does this same exact thing. The best way I could explain it is like the OP said, given an example I'm coasting at a speed of around 30mph or more and I give it gas, it's as if only 1 wheel responds. Which would allow it to pull left or right instead of straight. I can press and release the accelerator several times in a row and the "swaying" increases.

Like mtbtim said above, check your front/rear upper/lower control arm bushings. Does it also pull to one direction during hard braking?

 

[Pauleyman]

Bringing this up again. I have the same problem.
Car was aligned 15k ago and it drove beautifully. I rebuild the front end before this alignment. Car is/was tight. The rear seems to step out when letting off accelerator at highway speeds. It will wobble on its own also but not constantly. I am suspecting alignment as it also gives a little tire squeal at low speeds in a parking lot when turning. It did this before the front end rebuild. Had MAJOR camber issues and crappy SPC camber hardware. I replaced it all with Toyota hardware, energy suspension bushings etc.
I have not replaced the rear bushings but they do not appear to have excessive play etc. Actually look good considering the mileage. Sway bar is tight. Front I could shake a half an inch before I replaced everything.
I have appointments for tire balance and an alignment. If neither of those fix it out come the wrenches again I guess. Comments?