In today’s high-speed society, our vehicles form the backbone of almost every aspect of our daily lives. We rely on our vehicles to run smoothly to get to work, go to the grocery store, and take vacations. Without our ability to move freely, many of our modern conveniences fall by the wayside.
Because of this, we quickly find ourselves in a state of despair, realizing that something is wrong with our vehicles. Unfortunately, occasional mechanical breakdowns are an inevitable part of vehicle ownership and must be addressed head-on.
Of the many symptoms associated with various types of mechanical difficulty, few are as frightening as the feeling that your vehicle jumps unexpectedly. These types of problems can occur when braking, slowing, or stopping, and usually raise serious concerns regardless of the current situation.
Read on to learn more about the possible reasons why your vehicle shakes when braking, slowing, or stopping.
See also: 9 reasons why your car sputters when Density
The reasons why a car jerks when braking
It is not uncommon for drivers to feel a “shoe” when braking. Although these problems are far from uncommon, they require special attention to remedy the current situation.
The following are some of the most common reasons a vehicle has when the brake pedal is depressed.
#1 – Warped rotors
Warped brake discs are the main cause of unpleasant sensations when applying the brakes of a vehicle. Over time, vehicle brake rotors can become warped due to overheating, excessive wear, or rapid cooling.
This distortion occurs when a vehicle’s brake pads push against the affected brake rotors, causing knocking.
See also: Replacement Rotors vs. Rejuvenation
#2 – ABS Activation
Activating a vehicle’s ABS (anti-lock braking system) valve will cause a noticeable sensation when stopping.
If you have tried to stop suddenly, especially in wet conditions, this effect is not alarming. However, if your vehicle’s ABS system begins to operate at random stops, additional diagnosis will be necessary.
#3 – brake booster in danger
Another likely cause of vehicle vibration and braking is a faulty vacuum-assisted brake booster.
A vehicle brake booster works by manipulating a vacuum diaphragm when a vehicle’s brake pedal is pressed. If this diaphragm is compromised in any way, it can become stuck during braking.
#4 – Seized brake caliper
A badly worn brake caliper can cause the vehicle to shake when the brakes are applied. These skips and jumps are the result of seizure that occurs when a vehicle’s brake pads wedge against their mating rotor.
In some cases, this condition is also accompanied by an audible clicking sound.
#5 – Steering wheel/suspension dimensions
The typical vehicle uses many different bushings (i.e., control arm bushings, shock absorber bushings, steering rack bushings, etc.) to dampen vibrations at the front of the vehicle.
However, these bushings tend to wear over time, resulting in a significant increase in vibration damping. This condition often manifests itself during braking.
Causes of a car stalling while slowing down
A vehicle can also jerk when slowing down, even without defined braking. The cause of this unusual vibration must be isolated and repaired as soon as possible.
These are some of the most common reasons why a vehicle shakes when stopped.
#6 – Transmission problems
A jerking sensation when stopping is usually a sign of a transmission-related problem, such as a bad valve body or TCM.
This is usually true for automatic and manual transmissions, as they try to control their speed based on the current situation. Further diagnostics will be required to determine the full extent of these problems.
#7 – Faulty MAF sensor
It is not uncommon for a faulty mass airflow (MAF) sensor to cause the engine to screech when a vehicle slows down. A mass air flow sensor provides feedback to the engine ECM/PCM regarding the amount of air flowing through the intake tract.
This information is used to calculate engine fuel settings in real-time. However, reporting inaccurate data can lead to combustion irregularities.
#8 – Ignition coils in danger
The engine’s ignition coils provide a timely spark to each individual cylinder. However, when an ignition coil begins to fail, it often results in low-speed misfires, which often feel like knocking or popping.
Although these problems can also occur when traveling at high speed, they are much more common when accelerating, because the relative engine load is greatly reduced.
#9 – Sticky Butterfly Body
In some cases, jerking may occur when the engine’s throttle body begins to bind. The throttle body acts as a metering device for all air entering the engine intake manifold for combustion.
If a throttle body becomes stuck or does not engage in the desired position to meet engine demand, there is often some type of hesitation.
#10 – Vacuum leak
Another common cause of vehicles shaking when slowing down is heavy vacuum leaks.
An older vehicle often relied on engine vacuum to assist with several critical functions, including EGR operation. Worse yet, a leak in a vehicle’s vacuum system can cause serious but occasional mishaps, often only noticeable when it comes to a complete stop.
The reasons why a car shakes when stopped
Although less common than the conditions described above, a vehicle can also shake significantly when stopped. For many, it is a source of anxiety and can cause some anxiety until it is cured.
These are some of the most common reasons why a vehicle shakes while at a complete stop.
#11 – Ignition System Problems
A screeching noise felt when starting at a stoplight can often be attributed to one or more problems in the ignition system. Some of these more common problems include worn spark plugs, aged spark plug wires, and faulty coils.
On older vehicles, these types of problems were often caused by a worn or damaged distributor cap or rotor hub.
#12 – Fuel delivery problems
A fault that is felt at idle is often caused by a problem in the engine’s fuel system. A vehicle can experience many fuel system problems, including a clogged fuel filter, faulty fuel pressure regulator, or faulty injectors.
Most of these problems seem to be more easily noticed when you are sitting in a parking lot or at a red light.
#13 – Inefficient air supply
An internal combustion engine requires a continuous supply of clean intake air at all times to facilitate its proper operation. If an engine runs out of air at any point, combustion efficiency and overall performance drop, often resulting in serious misfires.
This conundrum can be easily detected at idle or during periods of low engine load. Problems of this type can be attributed to body defects or prolonged use of a dirty or clogged air filter.
#14 – Vacuum leak
Vacuum leaks are among the most common causes of rough idling, due to their unmetered supply of air into the engine’s intake tract. The engine ECM/PCM does not take this air into account, leaving it in very poor condition.
As a result, combustion efficiency is significantly reduced and engine performance drops to unprecedented proportions.