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Home / Symptoms / Jerking When Accelerating at Low Speeds

Hey, Why is My Car Jerking When Accelerating at Low Speeds?

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Four common causes for a vehicle jerking when driving at low speeds and their related parts.

The vehicle's engine can be a very complex machine. It needs to have fuel, air, and spark in the appropriate amounts and at the appropriate times. You can have electrical issues that inhibit the timing and control of various engine components, which will cause the vehicle to jerk when malfunctioning. You can also have mechanical issues that inhibit the amount of fuel and air getting to the engine and out of the engine, which, when they malfunction, will also cause the vehicle to jerk.

Is Your Car Jerking When Accelerating at a Low Speed?

The jerking is commonly caused by a disruption in the engine's fuel flow, resulting in sputtering and jerky movements. This is typically because of dirty fuel injectors, broken spark plugs, or faulty ignition coils. Jerking can also occur due to other factors, like debris in the mass airflow sensor, damaged plug wires, or a faulty throttle position sensor.

If the car jerks when accelerating at low speeds, it is advisable to consult a skilled professional for a comprehensive diagnosis. Their expertise and experience will ensure an accurate identification of the underlying cause.

Maintaining your vehicle's well-being is not merely a convenience; it also ensures your safety and peace of mind. These sudden jolts prevent your car from maintaining a constant speed, affecting its reliability. By promptly addressing the jerking issue, you can prevent potential complications and regain your confidence on the road.

Let's Get To The Bottom Of It!

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.

Have the vehicle's fuel economy suddenly worsened?

In a gasoline car engine, small parts called "fuel injectors" spray fuel into the engine before it ignites. Over time, these parts can get dirty and clogged from lack of maintenance. If that happens, the injector won't be able to spray the fuel, only dribble it out, making it harder to ignite. This causes the fuel to not burn completely in the engine cylinder, leading to lower performance and fuel economy.

Is the engine idling rough?

Idling rough is when the engine runs unevenly or inconsistently when the vehicle is standing; this can happen due to damaged spark plug wires. Spark plug wires are responsible for carrying high voltage to the spark plug, which creates a spark to ignite the fuel in the engine cylinder. If these wires become brittle, cracked, or damaged, the high-voltage spark can short to the ground instead of reaching the spark plug. In the future, this damage can result in faulty spark plugs. This prevents the cylinder from firing properly, resulting in a rough idle and car jerks when accelerating slowly.

Is the "check engine" flashing on the dashboard and the car struggles to start in cold weather?

The spark plugs in your car help light a small fire inside the engine that makes it go. But spark plugs have a tough job because they must work in hot and harsh conditions. As you use your car, the spark plugs will wear out over time, and the gap will get bigger. This can make them weaker and not as hot, which can cause problems. When it's freezing outside, this problem gets even worse. If your spark plugs are already worn out, your engine might not be able to start at all, or it might run rough until the engine warms up.

Is the "check engine" warning lighting up when you accelerate?

The ignition coil is an essential component of your car's engine that converts low voltage into high voltage in the battery, igniting the spark plugs. The high-voltage side of the coil requires good insulation to avoid going to the ground instead of the engine's spark plug. If the insulating boot between the coil and spark plug gets damaged, cracked, or soaked with oil or coolant, it causes the coil to short-circuit and fail. If the coil fails, the engine computer detects a misfire and triggers the check engine light on the dashboard.

Is the vehicle idle surging?

Idle surging is an irregular fluctuation in engine speed while the vehicle is stationary and not in motion. This is managed by the throttle position sensor, which detects the position of the throttle plate in the engine. If it malfunctions, the engine's computer may have difficulty accurately controlling the idle speed, leading to unstable idle and surging.

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Vehicle Health Inspection Proof

Explore the following typical inspection results that show a potential cause for the symptom and select the one you believe is similar to your vehicle's issue.

Damaged Plug Wire

A customer was concerned about their vehicle's poor idle quality and wondered if the spark plugs needed replacement. They took the car to the shop.

During the test drive, the technician observed that the vehicle was idling poorly, and the check engine light was active on the dashboard.

During the vehicle health inspection, there were no apparent issues related to the customer's concern. However, the technician scanned the vehicle's computer to investigate further and discovered a trouble code (P0308) indicating a misfire in cylinder 8.

With the customer's authorization for additional diagnostics, the technician used a specialized scanner designed for this particular vehicle to confirm the trouble code. The technician examined the stored data and found multiple misfire codes associated with cylinder 8.

While investigating this new information, the technician noticed that the spark plug wire for cylinder 8 had been damaged due to contact with the exhaust. Additionally, the spark plugs showed signs of wear.

To address these problems, the technician recommends replacing the distributor cap, rotor, and spark plug wires. Furthermore, they suggest installing a wire loom to protect the wires and spark plugs from potential damage in the future.

Ignition coil is faulty and triggering the check engine light on the dashboard while also causing engine sputtering and vibrations

When the customer brought in their vehicle, they complained about experiencing jerking sensations when accelerating. They also mentioned that the check engine light was constantly lit and would start flashing when the jerking occurred.

The technician confirmed that the check engine light was illuminated during the test drive. When the vehicle was accelerated forcefully, it had a big misfire, causing the check engine light to flash.

During the vehicle health inspection, nothing tracked the customer's concerns. To investigate further, the technician scanned the vehicle's computer and discovered a trouble code (P0303) indicating a misfire in cylinder 3.

With the customer's approval for additional diagnostics, the technician used a specialized scanner for this vehicle. They examined the log history of misfires and found that cylinder 3 had multiple occurrences of misfires, although it wasn't misfiring at idle. The technician increased the engine load to test the issue further, and cylinder 3 began misfiring.

To inspect the components related to cylinder 3, the technician accessed the coil and spark plug, which appeared to be in acceptable condition. Moreover, the technician swapped the coil from cylinder 3 with the one from cylinder 1 and the spark plug from cylinder 3 with the one from cylinder 6.

Then, they started the vehicle and gave it a heavy load. As a result, the misfire shifted to cylinder 1, thus verifying that the coil originally in cylinder 3, although seemingly fine, was beginning to fail.

Based on these findings, the technician recommends replacing all six coils, as they are all of the same age and could potentially develop similar issues. Additionally, it is advised to replace the spark plugs as a maintenance recommendation.

Dirty Maf Sensor

When the customer dropped off their vehicle, they mentioned two main concerns. First, the check engine light was on. Second, they experienced a lack of power and jerking when trying to accelerate from a standstill.

During the test drive, the technician noticed that the vehicle didn't respond well, and there were instances where it would jerk before the engine caught up and the vehicle started moving. The technician confirmed that the check engine light was indeed illuminated.

During the vehicle health inspection, the technician discovered that the air filter was damaged, allowing unfiltered air to enter the engine's intake system. Additionally, the technician scanned the vehicle's computer and found a code (P0101) indicating a malfunctioning mass airflow sensor.

To further investigate, the technician used a specialized scanner designed for this particular vehicle to confirm the code. By monitoring the live data from the vehicle, the technician observed that the calculated load was unusually low. Upon inspection of the mass air flow sensor and throttle body, the technician found a leaf lodged in the mass air flow sensor and a heavily dirty throttle body.

To address the problem, the technician cleaned the mass air flow sensor using a specific cleaner and reinstalled it while clearing the error codes. Afterward, the technician test-drove the vehicle and confirmed that the drivability issue had been resolved, and the engine ran normally.

Due to the damaged air filter, the technician recommends replacing it and performing an upper intake cleaning service to ensure optimal performance.

Dirty Injectors

When the customer brought in their vehicle, they expressed concerns about the dropping fuel economy. They were unsure if it was due to the gas quality or an issue with the vehicle.

During the test drive, the technician didn't notice anything about the customer's concern. Furthermore, during the vehicle health inspection, nothing showed what was causing a decrease in fuel economy.

With the customer's authorization for additional diagnostics, the technician used a specialized scanner for this vehicle. They checked for any trouble codes in the vehicle's modules but found none. While monitoring the live data, the technician noticed the calculated load was higher than normal.

Upon inspecting the throttle body, the technician found clogged and dirty fuel injectors. Therefore, the technician recommends a gas direct injection fuel service to address this issue and improve air fuel mixture. This service involves cleaning the throttle body and the injectors.

The customer agreed to proceed with the recommended service, and after it was performed, the calculated engine load dropped by 10% and returned to the normal range.

Broken Spark Plug

A customer mentioned having difficulty starting their vehicle since the outside temperatures have dropped.

During the test drive, the technician didn't notice any issues related to the customer's concern. Similarly, during the vehicle health inspection, the technician found nothing that could be causing the problem.

To further diagnose the issue, the customer authorized additional diagnostics. The technician used a specialized scanner designed for the vehicle to check for error codes. They found a P0300 code, indicating a random cylinder misfire, and a P0302 code, indicating a misfire in cylinder 2.

However, apart from the error codes, the technician didn't observe any actual misfires occurring at that moment. But, he visually could confirm that there were some worn out spark plugs in the system.

To investigate further, the technician removed the spark plugs from the engine. Based on the mileage, it was determined that the spark plugs were due for replacement. Additionally, the technician noticed that the porcelain of the number two spark plug was cracked. As a result, the technician recommends replacing all the spark plugs to address the issue.

Tps Failing

A customer dropped off their vehicle concerned that the engine felt like going to stall unless they pressed the accelerator pedal while the car was stationary. This issue got even worse when the vehicle was in gear.

During the test drive, the technician confirmed that the engine idle was unstable and fluctuating. Additionally, they noticed that the check engine light was illuminated.

During the vehicle health inspection, no obvious indications could explain the customer's concern. To investigate further, the technician scanned the vehicle's computer and discovered a trouble code (P0120) related to a malfunction in the throttle position sensor.

With the customer's approval for additional diagnostics, the technician used a specialized scanner for this vehicle. While monitoring the live data, they observed that the idle air control valve constantly adjusted position. Furthermore, the throttle position sensor provided inconsistent readings even when the throttle wasn't being pressed.

To accurately assess the throttle position sensor, the technician connected a lab scope to it and performed a throttle sweep. This test confirmed that the throttle position sensor malfunctioned and must be replaced and recalibrated.

Typical Fixes to Address the Cause(s)

The following chapters bases themselves on experiences from our auto repair shop; we'll describe related problems' causes and fixes.

Sometimes a problem is more challenging to describe than it initially looked like. If you are not sure your problem is described by this article, please find below similar vehicle symptoms, which might describe better the issue you are experiencing.

Vehicle Symptoms

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

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

Hey, Why Does My Car Jerk When Accelerating?

The car jerks when its not getting enough air or fuel or if therersquo...
Four common causes for the vehicle engine sputtering and their related parts.

Hey, Why Is My Car's Engine Sputtering?

The engine is sputtering because of a faulty fuel pump or mechanical f...

Typical Fixes Pages