Why Your Car Jerks at 20 MPH and How to Fix It

Last Updated on 9 months by Saifuddin Masuk

Car jerking at 20 mph can be a frustrating and alarming experience for any driver. It can cause your vehicle to shake or jolt, leading to discomfort and safety concerns. The problem can be caused by a wide range of mechanical and electrical issues, including damaged spark plugs, failing transmission, or disrupted electronic control module. Whatever the root cause, it’s crucial to identify and fix the issue as soon as possible to avoid more significant problems down the road.

Identifying the cause of the problem is essential as it can help prevent costly repairs and replacements. In some cases, a simple fix like cleaning the fuel injectors or replacing the oxygen sensor can do the trick. However, if the problem persists, it can lead to more significant issues, resulting in a much more expensive repair. This is why it’s essential to diagnose the problem accurately and promptly and fix it before it causes further damage.

In this article, we will delve deeper into the causes of car jerking at 20 mph, the symptoms that you should look out for, and how to diagnose and fix the problem. We’ll also discuss some preventative measures to help you avoid the issue altogether. Whether you’re a seasoned driver or a novice, this article will provide you with the knowledge you need to ensure your car runs smoothly and safely.

What is car jerks at 20 mph?

“Car jerks at 20 mph” refers to a common problem where a car experiences a sudden and irregular motion or jolt while traveling at a speed of 20 miles per hour. This jerking motion may feel like a sudden vibration or shudder, and can occur for a variety of reasons, including mechanical and electrical issues within the car’s engine or transmission system. It can affect the car’s overall performance and safety, so it’s important to diagnose and fix the problem as soon as possible.

Symptoms of Car Jerking at 20 MPH

Car jerking at 20 mph can be alarming and uncomfortable, and it’s essential to know the symptoms so that you can diagnose and fix the problem as soon as possible. Here are some of the most common symptoms of car jerking at 20 mph.

• Description of the car jerking

Car jerking at 20 mph can feel like a sudden jolt or vibration that occurs when you are driving at this speed. The jerking may occur intermittently or continuously, and it may feel like the car is hesitating or struggling to maintain a consistent speed. In some cases, you may also hear strange noises coming from the engine or transmission system.

• Effects on the car’s performance

Car jerking at 20 mph can have a significant impact on your car’s overall performance. It can cause the engine to run rough or stall, leading to reduced acceleration and power. The jerking can also affect the car’s fuel efficiency, causing it to use more gas than usual. If left unaddressed, the problem can worsen over time, leading to more significant issues that can be expensive to repair.

• Safety concerns

Car jerking at 20 mph can also pose a safety risk to you and your passengers. The sudden jolts and vibrations can make it difficult to maintain control of the car, especially if you’re driving on a busy road or at high speeds. If the problem is caused by a failing transmission, it can also cause the car to suddenly shift gears or lose power, leading to dangerous situations on the road.

If you notice any of the symptoms of car jerking at 20 mph, it’s essential to take your car to a mechanic as soon as possible. Not only can it affect your car’s performance and fuel efficiency, but it can also pose a safety risk to you and your passengers. By addressing the problem promptly, you can avoid more significant issues and ensure that your car runs smoothly and safely.

Why does my Car Jerking at 20 MPH

Car jerking at 20 mph can be caused by various mechanical and electrical issues, and it’s essential to identify the root cause so that you can address the problem effectively. Here are some of the most common causes of car jerking at 20 mph.

Mechanical Issues

1. Worn spark plugs: Spark plugs are responsible for igniting the fuel in the combustion chamber, and when they wear out, they can cause the engine to misfire, leading to car jerking.
2. Dirty fuel injectors: Fuel injectors can become clogged with dirt and debris over time, leading to a disruption in the fuel supply and resulting in car jerking.
3. Failing transmission: A failing transmission can cause car jerking at 20 mph, as it struggles to maintain a consistent speed and shift gears.
4. Damaged drive shaft: A damaged drive shaft can cause car jerking, especially when driving at high speeds, as it affects the power transmission to the wheels.
5. Malfunctioning suspension system: A malfunctioning suspension system can cause car jerking, as it affects the car’s stability and handling.

Electrical Issues

1. Failing oxygen sensor: The oxygen sensor is responsible for regulating the fuel mixture in the engine, and when it fails, it can cause car jerking and reduced fuel efficiency.
2. Malfunctioning mass airflow sensor: The mass airflow sensor measures the air coming into the engine and regulates the fuel mixture, and when it fails, it can cause car jerking.
3. Faulty throttle position sensor: The throttle position sensor regulates the amount of air and fuel going into the engine, and when it fails, it can cause car jerking and reduced acceleration.
4. Damaged ignition coil: The ignition coil is responsible for generating the spark that ignites the fuel in the combustion chamber, and when it fails, it can cause car jerking.
5. Disrupted electronic control module (ECM): The electronic control module regulates various systems in the car, including the engine and transmission, and when it becomes disrupted, it can cause car jerking.

Other Possible Causes

1. Clogged air filter: A clogged air filter can reduce the airflow to the engine, leading to car jerking and reduced acceleration.
2. Low fuel pressure: Low fuel pressure can affect the fuel supply to the engine, leading to car jerking.
3. Contaminated fuel: Contaminated fuel can cause car jerking, as it affects the fuel quality and combustion in the engine.
4. Vacuum leaks: Vacuum leaks can cause car jerking, as they disrupt the air and fuel supply to the engine.
5. Bad torque converter: A bad torque converter can cause car jerking, as it affects the power transmission from the engine to the wheels.

In conclusion, car jerking at 20 mph can be caused by various mechanical and electrical issues, and it’s essential to identify the root cause so that you can fix the problem effectively. By addressing the issue promptly, you can avoid more significant problems down the road and ensure that your car runs smoothly and safely.

Diagnosis of Car Jerking at 20 MPH

Diagnosing the cause of car jerking at 20 mph can be a daunting task, especially if you’re not familiar with the car’s inner workings. However, by following these steps, you can identify the root cause of the problem and fix it effectively.

Steps to diagnose the problem:

1. Check the dashboard for warning lights: Check if any warning lights are on, as they can indicate which system is malfunctioning.
2. Test drive the car: Take the car for a test drive and observe when the jerking occurs, such as during acceleration, deceleration, or cruising.
3. Listen for unusual sounds: Listen for any unusual sounds, such as clicking or grinding, which can indicate a mechanical issue.
4. Check the fluid levels: Check the fluid levels, such as oil, transmission, and coolant, as low levels can cause car jerking.
5. Inspect the components: Inspect the components, such as spark plugs, fuel injectors, and suspension, for signs of wear and damage.

Tools needed for diagnosis:

To diagnose the problem, you’ll need the following tools:

1. Diagnostic scanner: A diagnostic scanner can read the car’s computer codes and provide a detailed report on which system is malfunctioning.
2. Multimeter: A multimeter can test the electrical components, such as the oxygen sensor and ignition coil, for proper voltage and resistance.
3. Compression tester: A compression tester can test the engine’s compression to determine if there are any mechanical issues.
4. Fuel pressure gauge: A fuel pressure gauge can test the fuel pressure to determine if there are any issues with the fuel supply.

Testing procedures:

To test the components, follow these procedures:

1. Test the spark plugs: Remove the spark plugs and inspect them for signs of wear and damage. Check the gap and resistance using a multimeter.
2. Test the fuel injectors: Use a fuel injector cleaner or remove the injectors and clean them thoroughly. Test them for proper flow rate and spray pattern.
3. Test the oxygen sensor: Use a multimeter to test the oxygen sensor for proper voltage and resistance. Replace it if it’s not functioning correctly.
4. Test the ignition coil: Use a multimeter to test the ignition coil for proper voltage and resistance. Replace it if it’s not functioning correctly.
5. Test the suspension: Inspect the suspension for signs of wear and damage. Test the shock absorbers and struts for proper compression and rebound.

In conclusion, diagnosing the cause of car jerking at 20 mph requires a systematic approach and the right tools. By following these steps and testing procedures, you can identify the root cause of the problem and fix it effectively. However, if you’re not comfortable with DIY diagnosis and repair, it’s best to consult a professional mechanic for assistance.

Fixing the Problem of Car Jerking at 20 MPH

Now that you’ve identified the cause of the car jerking at 20 mph, it’s time to fix the problem. Depending on the cause, there are various repairs that you can perform to get your car running smoothly again.

Mechanical Repairs:

1. Replacing spark plugs: If the spark plugs are worn or damaged, they can cause the engine to misfire, resulting in car jerking. Replace the spark plugs with new ones to ensure proper ignition.
2. Cleaning fuel injectors: Dirty fuel injectors can cause poor fuel flow, leading to engine misfire and car jerking. Clean the fuel injectors or replace them if necessary.
3. Repairing transmission: If the transmission is failing, it can cause car jerking at 20 mph. Take your car to a professional mechanic to diagnose and repair the transmission.
4. Replacing drive shaft: A damaged drive shaft can cause vibration and car jerking. Replace the drive shaft to restore smooth operation.
5. Fixing suspension system: A malfunctioning suspension system can cause the car to bounce and jerk at 20 mph. Replace worn components, such as shock absorbers and struts, to improve ride quality.

Electrical Repairs:

1. Replacing oxygen sensor: A failing oxygen sensor can cause car jerking and reduced fuel efficiency. Replace the oxygen sensor to restore proper engine operation.
2. Repairing mass airflow sensor: If the mass airflow sensor is malfunctioning, it can cause engine misfire and car jerking. Repair or replace the sensor as needed.
3. Fixing throttle position sensor: A faulty throttle position sensor can cause poor acceleration and car jerking. Replace the sensor to improve throttle response.
4. Replacing ignition coil: A damaged ignition coil can cause engine misfire and car jerking. Replace the coil with a new one to restore proper ignition.
5. Repairing electronic control module (ECM): If the ECM is disrupted, it can cause engine misfire and car jerking. Repair or replace the ECM as needed.

Other Repairs:

1. Changing air filter: A clogged air filter can cause poor engine performance and car jerking. Replace the air filter with a new one to improve airflow.
2. Increasing fuel pressure: If the fuel pressure is too low, it can cause engine misfire and car jerking. Increase the fuel pressure to ensure proper fuel delivery.
3. Flushing contaminated fuel: If the fuel is contaminated, it can cause poor engine performance and car jerking. Flush the fuel system and replace the fuel with clean gasoline.
4. Fixing vacuum leaks: If there are leaks in the vacuum system, it can cause engine misfire and car jerking. Fix the leaks to ensure proper engine operation.
5. Replacing torque converter: If the torque converter is failing, it can cause car jerking and transmission problems. Replace the torque converter to restore smooth operation.

In Summary, fixing the problem of car jerking at 20 mph requires a targeted approach and the right tools. By performing the necessary mechanical, electrical, and other repairs, you can restore your car’s smooth operation and enjoy a comfortable ride. If you’re not comfortable with DIY repairs, it’s best to consult a professional mechanic for assistance.

Preventing Car Jerking at 20 MPH

Car jerking at 20 MPH is not only frustrating but can also be a safety concern. To prevent this problem from occurring in the future, it is essential to practice good car maintenance and driving habits. Here are some tips to help you prevent car jerking at 20 MPH.

Regular car maintenance

Regular car maintenance is the best way to prevent car jerking. Some of the essential maintenance tasks include regular oil changes, filter replacements, and tune-ups. It is also essential to have a professional mechanic inspect your car regularly to identify and fix any potential problems before they become bigger issues.

Using high-quality fuel and lubricants

The type and quality of fuel and lubricants used in your car can also affect its performance. Low-quality fuel or lubricants can cause build-up in the engine, leading to problems such as car jerking. It is essential to use high-quality fuel and lubricants recommended by the car manufacturer to ensure optimal performance and prevent car jerking.

Proper driving habits

Your driving habits can also contribute to car jerking. Avoid harsh acceleration and sudden braking as these can put a strain on your car’s engine and transmission. It is also important to avoid overloading your car with excessive weight as this can put undue stress on the suspension and drivetrain.

Car jerking at 20 MPH can be a frustrating and potentially dangerous problem. However, with proper diagnosis, repair, and preventative measures, you can eliminate this issue and enjoy a smooth ride. Regular car maintenance, using high-quality fuel and lubricants, and practicing proper driving habits are essential to preventing car jerking.

Conclusion

Car jerking at 20 MPH can be caused by various mechanical, electrical, and other issues that we have discussed in this article. Some of the most common causes include worn spark plugs, dirty fuel injectors, failing transmission, damaged drive shaft, malfunctioning suspension system, and electronic issues.

It is crucial to diagnose and repair the problem immediately as it can lead to more significant issues and safety concerns. Regular car maintenance, using high-quality fuel and lubricants, and proper driving habits are essential to prevent car jerking.

If your car is experiencing jerking at 20 MPH, the first step is to diagnose the problem by performing tests and using the appropriate tools. Once the issue is identified, there are various solutions available, including mechanical repairs, electrical repairs, and other fixes.

In summary, diagnosing and fixing the issue of car jerking at 20 MPH can help you avoid potential safety risks and ensure a smooth ride. With the right diagnosis, tools, and repairs, you can restore your car’s performance and prevent this issue from happening again in the future.

FAQs

• What is the main cause of car jerking at 20 MPH?

Car jerking at 20 MPH can be caused by various issues such as worn spark plugs, dirty fuel injectors, failing transmission, damaged drive shaft, malfunctioning suspension system, and electronic issues.

• Can I fix the problem myself?

It is possible to diagnose the problem yourself, but fixing it requires technical expertise and specialized tools. It is recommended to seek help from a professional mechanic for proper diagnosis and repair.

• How long does it take to repair the issue?

The time it takes to repair the issue depends on the cause of the problem and the extent of the repairs needed. Some repairs may take only a few hours, while others may take several days.

• How much does it cost to fix the car jerking problem?

The cost of fixing the car jerking problem varies depending on the cause of the issue and the extent of the repairs needed. Simple repairs like changing spark plugs may cost a few hundred dollars, while more complicated repairs like transmission replacement can cost thousands of dollars.

• Can I still drive my car if it jerks at 20 MPH?

It is not recommended to drive your car if it jerks at 20 MPH as it can cause safety concerns and lead to further damage. It is best to have the problem diagnosed and repaired as soon as possible.

• Why does my car jerk at 40 MPH?

There could be several reasons why your car only jerks at 40 MPH and not at other speeds. One possibility is that this speed range is where a particular issue with the engine, transmission, or drivetrain becomes most apparent. It could also be related to the way the car’s computer is programmed to adjust to different driving conditions. It is best to get your car diagnosed by a mechanic to determine the underlying cause of the issue.

• Why does my car jerk at 30 MPH?

There could be several reasons why your car only jerks at 30 MPH and not at other speeds. One possibility is that this speed range is where a particular issue with the engine, transmission, or drivetrain becomes most apparent. It could also be related to the way the car’s computer is programmed to adjust to different driving conditions. It is best to get your car diagnosed by a mechanic to determine the underlying cause of the issue.

• Is it safe to drive my car if it jerks at 30 MPH?

While it may be possible to drive your car if it jerks at 30 MPH, it is not recommended. The jerking may be a sign of a larger problem that could worsen over time and potentially cause more serious damage to your car. Additionally, driving a car that is not running smoothly can be unsafe and may cause issues with handling and braking.

• Can I continue to drive my car if it jerks at 40 MPH?

While it may be possible to drive your car if it jerks at 40 MPH, it is not recommended. The jerking may be a sign of a larger problem that could worsen over time and potentially cause more serious damage to your car. Additionally, driving a car that is not running smoothly can be unsafe and may cause issues with handling and braking.

• How much does it cost to fix a car that jerks at 40 MPH?

The cost of fixing a car that jerks at 40 MPH can vary widely depending on the underlying cause of the issue. Some fixes, like replacing spark plugs or air filters, may be relatively inexpensive, while others, like transmission work, can be more costly. It is best to get an accurate estimate from a qualified mechanic before proceeding with any repairs.