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Home / Symptoms / Jerking When Accelerating

Four common causes for the vehicle jerking when accelerating and their related parts.

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Is Your Car Jerking When You Accelerate It?

The car jerks when it's not getting enough air or fuel or if there’s a transmission problem. It's struggling to breathe or get enough gas because of dirty fuel injectors, clogged air filters, or worn spark plugs. Plus, when the transmission has trouble changing gears smoothly, it can give the car a bumpy ride.

Watch out: To understand why the car jerks while accelerating, it's recommended to seek the expertise of a qualified professional. They have the knowledge and experience to diagnose the underlying cause accurately. A car jerking when accelerating needs proper care. By addressing the jerking issue promptly, you can avoid further complications and enjoy the open road with confidence.

The most common causes for the car jerking when accelerating

The most common causes for a car jerking when accelerating:

Faulty spark plug boots: The spark plug boots are rubbery protections connecting combustion components to the spark plug; they’re necessary because of their insulation, shielding the electrical current from the spark plugs that travel through to the engine. However, if the spark plug boots fail, the electrical current might struggle to get across properly, resulting in jerks, sputters, and engine misfires, even when accelerating.
Faulty transmission control: The TCM (Transmission Control Module) is where all the mathematics about your vehicle’s transmission happen. This module gets the readings from sensors and the driver’s transmission movements to automatically shift gears (in automatic cars) and adapt the vehicle’s response to certain driving demands. However, if this control module fails, your vehicle’s transmission starts making mistakes like shifting the wrong gears or rough idling, resulting in jerks when accelerating.
Faulty throttle body: The throttle body is a component that controls the amount of air that enters the engine; it’s an airflow component from the vehicle’s cooling system. Therefore, the throttle body is essential for managing vehicle temperature and it works by opening and closing a valve based on whatever the driver is doing with the accelerator. This way, the valve opens to allow air inside the engine during acceleration, so combustion can work its best to provide power. However, if the throttle body fails, this valve allowing air to enter the system might stop working, resulting in bad airflow, obstructions, engine misfires, and jerking.
Faulty mass airflow: The mass airflow is the amount of air that enters the engine during combustion, which is measured by the Mass Airflow Sensor. This component makes internal calculations to understand how much air is entering the engine so it can determine how much fuel to inject, making combustion work its best. However, if this component fails, these air calculations go wrong, resulting in the engine struggling to combust efficiently, causing jerkings when accelerating.
Faulty fuel pump: The fuel pump pushes fuel so it can reach components that need it at the right time. The engine particularly needs fuel at a specific time and amount so it can combust efficiently while the vehicle drives. However, a faulty fuel pump struggles to push enough fuel timely, resulting in combustion issues like engine misfires, sputtering, and jerking when accelerating.
Poor air filter: The air filter is an essential airflow component that helps keep the air circulating inside the vehicle and reaching the engine clean. Therefore, the air filter is a high-priority air quality component. However, if the air filter is too old, worn, and clogged, the air quality inside the engine drops, and vapors might become obstructed, resulting in a buildup that causes the engine to misfire, sputter, and jerk when accelerating.

Frequently Asked Questions

Have you noticed a recent fuel economy drop?

The engine air filter has an important job: it stops dirty stuff like dust and junk from getting inside the engine. But if the air filter gets all filled up or blocked because of driving habits and lack of cleaning, air struggles to pass through. This means the engine won't have as much power or speed and will use more fuel, making it less efficient. At this stage, jerks during acceleration are common.
Is the vehicle's "check engine" light active on the dashboard?

The mass air flow sensor tracks how much air goes into the engine. It tells the passing air volume and speed to the engine's computer. This helps the system determine how much fuel the engine needs to run smoothly, enabling enough power and speed. It also helps reduce pollution. But if the mass air flow sensor doesn't measure the air correctly, other sensors in the engine and exhaust will notice something's off and tell the computer; this can happen due to debris or wear. Then, the check engine light will turn on as a warning. At this stage, the car might commonly sputter when accelerating.
Does the "check engine" light starts flashing when there's a heavy load in the engine?

The spark plug boots have an essential job. They connect to the coil and fit over the spark plug to protect it from grounding out, preventing a misfire in that cylinder. Unfortunately, these boots are rubber and can deteriorate over time. If this happens, the high-voltage spark can create a carbon pathway along the spark plug and boot, preventing the boots from isolating power. This leads to a misfire in the cylinder and triggers the check engine light to start flashing. In addition, when the engine is under a heavy load, the ignition system has to work harder, making the misfire more noticeable and causing acceleration jerks.
Is the vehicle unexpectedly shifting gears?

The transmission control module manages the transmission; it considers how much work the engine does and what the car needs gear-wise. But if, for any reason, the transmission control module isn't working correctly, it can cause the transmission to shift in strange and unexpected ways. This means the car's behavior might become unpredictable, and you may experience random jerks and shifting of gears.
Apart from jerking, is the car also stumbling when accelerating?

The fuel pump is like a special pump that runs on electricity and hydraulics. It's inside the fuel tank, and its job is to ensure enough pressure and fuel flow to the injectors. This way, the engine always has fuel to keep running no matter how you drive. But as the pump gets older, it starts to wear out. This means it won't create as much pressure and fuel flow as before. So, when you try to accelerate quickly, the engine won't get what it needs and will feel like it's stumbling or jerking.
Is the vehicle's throttle feeling like it has no control?

The throttle body is like a special valve that controls how much air goes into the engine. In today's engines, it's controlled by a small motor that's controlled by the computer that runs the engine. However, the throttle body can develop problems over time because of wear and heat. This can cause the throttle body to malfunction in certain situations, making it difficult to control the engine when pressing the gas pedal.

Typical fixes to address the cause(s)

These are typical processes and repair services that fix a check engine light issue

The most common cause: Poor air filter

The most common reason for a car jerking when accelerating is due to a poor air filter causing cooling and airflow issues. The air filter is essential to keep the air inside the engine clean and debris-free. However, if the air filter gets too old, worn, and clogs up, the air that circulates inside the engine gets heavier and low on quality. Additionally, the air that should leave the engine might become obstructed by the clogged air filter, resulting in a buildup of vapor and gases that overheat the engine, leading to further combustion issues.

Symptoms it causes: Apart from the vehicle jerking when accelerating you might notice engine misfires, engine sputters, rough idling, engine stalling, lawnmower noises, etc.
High risk of priority: A clogged fuel filter can obstruct the airflow inside the engine, leading to cooling issues. Consequently, the engine might misfire, lose performance, consume fuel excessively, stall, or even break down, in the worst cases.

How exactly do fuel filters get bad?

Fuel filters naturally get bad over time; they’re exchangeable items that you need to regularly check during maintenance sessions. A filter can only accumulate so much debris and particles since it removes these impurities from the air and holds them to itself. Typically, a good rule of thumb is to check the air filter at regular maintenance and replace it every 30,000 miles.

Go safe: Ask for a mechanic to inspect your vehicle’s combustion system to investigate if the air filter is dirty due to surrounding components and if there’s further damage to check out. Many shops do transparent vehicle inspections and lay out your options after investigating your vehicle’s conditions.

What’s a vehicle inspection? It’s “detective work” on your vehicle, checking its systems to see if anything prevents the car from working as expected. In this case, mechanics examine different parts of your vehicle to track if anything is causing the air filter to become dirty. They’ll also check the condition of components during their inspection, noting which are causing the problem and which got affected by it, recommending to replace them in order of priority.

Transparency example in a bad air filter service

A combustion system inspection is the most transparent process to understand why your vehicle’s air filter is bad. This is because many components surrounding the air filter and air intake components can have a say in the issue, indicating the real culprits that caused it all.

Let’s read an example of how this kind of inspection helps to service a bad air filter and solve a jerking when accelerating issue.

When the customer brought in their vehicle, they mentioned their fuel economy worsened. They used to get around 29 miles per gallon, but now they only get about 25 and the car would vibrate a little. They wondered if the change was because of the winter season.

The customer also told about a jerking sensation from the car, which occurred at that same time.

During the test drive, the technician didn't notice anything directly related to the customer's concern. However, during a vehicle health inspection, the technician found that the engine air filter was almost completely blocked and needed replacing.

The technician used a special scanner designed for this vehicle to investigate further. First, they checked for any trouble codes in the vehicle's modules, but none were found. The technician then monitored live data and noticed that the fuel trims were minus seven.

Notice that the fuel trim values can be positive or negative, indicating whether the ECU (Engine Control Unit) adds or reduces fuel to achieve the desired mixture. In this case, it was reducing the fuel amount.

To confirm the cause of the reduced fuel economy, the technician removed the air filter while the engine was running. They observed that the fuel trims immediately improved, fluctuating between plus and minus three. This verified that the clogged air filter was the reason behind the decrease in fuel economy.

Poor air filter causing the engine to have a bad airflow, resulting in overheating, vibrations, and warnings

In this case, the mechanic put the “Immediate Action” tag on the air filter.

Similar Symptoms

Below are just a few examples of typical Symptoms and Fixes your car might be experiencing

Four common causes for weird braking from a vehicle and their related parts.

Is Your Car Jerking When You Accelerate It?

The most common causes for the car jerking when accelerating

Frequently Asked Questions

Have you noticed a recent fuel economy drop?

Is the vehicle's "check engine" light active on the dashboard?

Does the "check engine" light starts flashing when there's a heavy load in the engine?

Is the vehicle unexpectedly shifting gears?

Apart from jerking, is the car also stumbling when accelerating?

Is the vehicle's throttle feeling like it has no control?

Typical fixes to address the cause(s)

The most common cause: Poor air filter

How exactly do fuel filters get bad?

Transparency example in a bad air filter service

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