Q: Q: Car shakes when I slow down.

asked by on

On the interstate I had to put the gas to the floor to speed up and get past someone then after that the vehicle shook and vibrated when I slowed down.

My car has 164000 miles.
My car has an automatic transmission.

Hello. The imbalance of rotating parts on a car, such as your wheel and tire assemblies, is a function of speed but also "positioning". When you were traveling at a steady state rate, say 65 MPH, the suspension was clearly capable of withstanding whatever residual imbalance exists in the rotating assemblies and thus the residual imbalance is essentially invisible to you (not felt).

Nothing that rotates on a car is ever perfectly balanced. Rather, the components are balanced just to the point where the residual imbalance creates ONLY vibration that is below the threshold of detection. The imbalance is there; it’s so small though your car suspension doesn’t transmit it through (the steering) wheel or vehicle frame. What is happening in your case when you suddenly accelerate and then completely unload the drive train (by taking your foot off the gas and coating) is you are changing the position of the rotating elements (wheels and tires) such that the imbalance that does exist is "magnified" and thence transmitted through the vehicle. The practical causes of this are worn tires and worn suspension parts that are not holding the wheel/tire assemblies in the same fixed position during coasting as during acceleration. That is the likely cause.

Was this answer helpful?
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
  1. Home
  2. Questions
  3. Q: Car shakes when I slow down.

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: My car does not move when I accelerate, the engine shakes when it is turned on and in a traffic it shakes sometimes.

Hi there. Check the engine for any misfiring conditions. Check the spark plugs and the fuel injectors and see if they are working properly. See if there is spark to the engine and see if the injectors are firing by...

Q: Car turns over but when in gear won't move 2009 Buick Enclave

Hello - check fluid level in the transmission, and for problem code, whether the Check Engine light is one or not. I suspect it will be. This sounds like a failure internal to the transmission, clutches, valve body or a...

Q: Chevy impala neutral safety switch

It is not clear if the check engine light and the other issues (the PRDNL light and the no start) are connected. The OBD-II trouble codes should be downloaded though as they may provide key clues to resolving this. You...

Related articles

What Causes Hoses to Leak?
While the largest part of your engine is mechanical, hydraulics plays a significant role. You’ll find fluids at work in a number of different areas. Your car's fluids include: Engine oil Transmission...
P0052 OBD-II Trouble Code: HO2S Heater Control Circuit High (Bank 2 Sensor 1)
P0052 code definition HO2S Heater Control Circuit High (Bank 2 Sensor 1) What the...
How Much Does a Mechanic Make in Vermont?
Automotive technician jobs in Vermont have an average mechanic salary of $37k, with some mechanics earning a salary of $53k.