Shaking when decelerating to a stop?

OdinWiski

OdinWiski

New member
Hey guys,

2006 V8 4x4 with about 108k miles. I've had this problem for a while - when I decelerate and crawl to a stop, the truck shakes and vibrates pretty bad, but does NOT shake or choke once stopped and is idling. Was wondering what might be the problem?

  • Even though it's coming from the front end, it's not the front rotors or brakes because when I brake at higher speed, the truck handles fine with no vibration. The shaking/vibration only comes on when braking in low speed TRYING TO COME to a stop. So it must be engine/fuel-air mix related. The shaking and vibration do transfer from the front end all the way to the rear window. I can feel the rear end vibrating as a result too.
  • It starts fine with no hestitation or rough idle. When the engine warms up, it idles at 500-650 rpm depending on whether AC is on.
  • After coming to a full stop, the truck STOPS shaking and idles at 500-650 rpm depending on whether AC is on. No choking, no hesitation. It idles smoothly. It only shakes during the course of COMING to a stop with or without applying brakes. When applying brakes at low speed, the shaking is a little more pronouced. But the shaking still happens even without applying brakes when trying to come to a stop. Also, NO shaking or vibration when accelerating from a stop or low speed.
  • Plugs were changed 5k ago. Denso plugs.
  • Throttle body was cleaned 5k ago.
  • MAF was cleaned 5k ago.
  • Brake fluid was changed 5k ago.
  • Air filter was changed 5k ago.
  • The problem was present before all the above maintenance was done.

Any thought what might be wrong? Thanks!
 
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If you don't have a check engine light then it's probably not your engine. Stuff that bad would have triggered one already. If anything you've got something wrong in your tranny or one of your CVs/joints binds at slower speeds.

Is there any noise when this happens? Do you have a CEL?
 
Last edited:
drewm said:
If you don't have a check engine light then it's probably not your engine. Stuff that bad would have triggered one already. If anything you've got something wrong in your tranny or one of your CVs/joints binds at slower speeds.

Is there any noise when this happens?
Click to expand...

No check engine light. CV axles were replaced just before those other maintenance items - they were leaking and trashed. No clicking sound when going straight or turning at low speeds. When the shaking and vibration come on, the droning sound coming from the vibration is pretty loud and basically drowns out everything else. Maybe I can try to film a short clip later when it happens. The consolation is it is NOT intermittent - it happens all the time! :)
 
Even though it's coming from the front end, it's not the front rotors or brakes because when I brake at higher speed, the truck handles fine with no vibration. The shaking/vibration only comes on when braking in low speed TRYING TO COME to a stop.
Click to expand...

I wouldn't eliminate brakes as the culprit just yet. It still could be the calipers.

Also since brakes use the Vacuum system...it could be a vacuum leak.
 
MikeInNH said:
I wouldn't eliminate brakes as the culprit just yet. It still could be the calipers.

Also since brakes use the Vacuum system...it could be a vacuum leak.
Click to expand...

Are you talking about calipers frozen? If that was the case, I think I would feel the vehicle pulling to the side when braking or other anomalies when applying brakes? And the shaking and vibration happens when brakes are not applied and just coasting to a stop also.

As far as a vacuum leak, that might be a possibility. But I thought having a vacuum leak would usually cause the vehicle to idle rough? Mine doesn't though.

I want to thank you for the input. That's what's great about this forum. Please keep them coming :)
 
Brake fluid is full btw. I was starting to think along the lines of brake booster or master cylinder, but the braking and pedal feel are normal otherwise and if it happens without brakes being applied also, I'm not sure it's related to brakes per se?

https://vimeo.com/102279995


Here's a clip to show what it's doing. You have to turn the volume up to hear the droning from the vibration, but it's pretty clear. The 3rd segment of the video is when the truck is just coasting without me giving it gas or brakes for the most part. And the shaking and vibration come on then too.
 
I run into this problem A LOT. Most of the time the rotors are warped, could be your driving style or maybe a defective rotor( but not unsafe in a sense). Take your rotors off and have them turned at a shop for less than $30 typically. If your not on a budget throw pads in while your at it( the proper thing to do) . All in all I'm just saying give your rotors a shot before you dive into wheel bearings or cv's, not much time or money needed for that
 
The 4th Gen 4Runner has no vacuum lines going to the braking system. Its an entirely self-contained hydraulically assisted unit.

When you talk about shaking, are you saying the engine/drivetrain shakes or that the steering wheel/front wheels are shaking?

Also if the engine/drivetrain is shaking, do the RPMs fluctuate and/or does the vehicle feel/sound like it is misfiring?
 
BlackWorksInc said:
The 4th Gen 4Runner has no vacuum lines going to the braking system. Its an entirely self-contained hydraulically assisted unit.

When you talk about shaking, are you saying the engine/drivetrain shakes or that the steering wheel/front wheels are shaking?

Also if the engine/drivetrain is shaking, do the RPMs fluctuate and/or does the vehicle feel/sound like it is misfiring?
Click to expand...

Thank you! Finally someone really read what had been said! LOL It feels like engine/drive train shaking, not the steering wheel or front wheel. As you can see in the video, RPMs do not fluctuate drastically (or at all?) when it does this. They might fluctuate just a tiny bit? But certainly not very discernable. I can't tell. Can you from the video? It feels exactly like the engine is going to stall, but the RPMs hold and it idles PERFECTLY after coming to a full stop. I'm not quite sure what misfiring would sound like?

Also, whoever commented on loud droning sound (probably in the second segment in the video), that was from the tires. The droning sound I'm talking about is when the deceleration is toward the end (when RPMs are just starting to dip below 1000) and just before the vehicle coming to a full stop. You can hear the vibration and loud buzzing from the dash and rear window etc. Once stopped, it goes away and everything is normal. Also, in the 3rd segment you can hear it doing it 2 or 3 times when the vehicle is just crawling at 5 mph at about 900 RPMs without me tapping on gas or brakes.
 
Have you had someone hold the brake and shift from park to reverse (rocking the engine) to see if the motor mounts are becoming weak/worn?

Do you notice some harsh shifting/movement other times that may indicate some issues with the mounts?

From your video it does not seem like the engine is really doing much in terms of running rough/misfiring/idling poorly; which makes me wonder if the issue is for some reason more pronounced when decelerating due to downshifting and/or other reasons?
 
BlackWorksInc said:
Have you had someone hold the brake and shift from park to reverse (rocking the engine) to see if the motor mounts are becoming weak/worn?

Do you notice some harsh shifting/movement other times that may indicate some issues with the mounts?

From your video it does not seem like the engine is really doing much in terms of running rough/misfiring/idling poorly; which makes me wonder if the issue is for some reason more pronounced when decelerating due to downshifting and/or other reasons?
Click to expand...

I had checked myself when the vehicle was idling and by trying to rock the motor to see whether the mounts were worn, but they seemed fine. I can have someone throw it in reverse while I look under the hood to see whether I see huge movement. Thank you for the suggestion.

I have not noticed any harsh shifting or movement other times.

Starting from 28 seconds, the vehicle was just crawling on its own from a stop without me giving input, no downshifting was involved. But as you can see it was still vibrating and buzzing for 3 times.

Also, it idles dead steady at 600-650 RPMs with no choking, hesitation, or RPM surge. No vibration or shaking.
 
After reading this.. I would tend to believe its some kind of broken mount. Not engine or braking related.. Very hard to tell without being in the vehicle though..

Like blackworks said.. maybe engine or a tranny mount? something thats getting a lot of stress put on it when decelerating and has the ability to vibrate when it normally wouldnt.
 
However.. I watched the video a few times.. and then I start to feel like its the brake pads installed incorrectly and vibrating in the caliper?
 
Billynath1988 said:
However.. I watched the video a few times.. and then I start to feel like its the brake pads installed incorrectly and vibrating in the caliper?
Click to expand...

Pads were done a long time ago and this had never happened until a few thousand miles ago? Do you think this would be the case when without applying brakes the shaking/vibration still comes on?
 
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