Car Wont Go Over 20 – 30 MPH: 10 Possible Reasons

Is your car struggling to reach its maximum speed? If your car wont go over 20 – 30 mph, there could be a multitude of reasons behind this frustrating issue. It not only affects your driving experience, but it can also be dangerous if you need to merge onto highways or keep up with the flow of traffic. 

Whether you have a modern vehicle or an older model, the root cause for the lack of speed can vary. In this article, we will explore ten possible reasons why your car may be unable to exceed 20-30 mph. From issues with the fuel system to problems with the transmission or tires.

Car Wont Go Over 30 MPH
Photo by: Pixabay

We will discuss each potential culprit in detail. Identifying the reason behind your car’s reduced speed is crucial to ensure a safe and efficient driving experience. So, let’s dive in and investigate the possible causes for your car’s inability to reach higher speeds.

Read Also: Car Steering Wheel Buttons Not Working: 10 Common Issues Fix

The Most Common Reasons Why Your Car Wont Go Over 30 MPH

The cause could vary from a straightforward fix to a much more costly repair, but regardless it’s crucial to determine the issue as soon as it occurs.

The most frequent reason for cars not reaching 30 mph is because it has entered the mode of limp. The safety features that is built into modern vehicles restricts the engine’s speed when something is wrong. The most likely reason for this could be a problem with the sensors in the car like the throttle or mass airflow sensor for position. When this happens, it’s a scenario, it’s likely to be resolved by a simple reset.

In this blog we’ll go over possible reasons your vehicle won’t be able to travel over 30mph. We’ll also discuss the steps you must follow to identify and correct the issue.

Car Wont Go Over 30MPH And Check Engine Light Is On

If your car can’t go over 30mph when the engine check light comes on, your car is in limp mode. Modern vehicles have a security feature called limp mode, which restricts the engine’s speed in order to prevent injury. This can be caused by several problems, a few of which we’ll address.

Photo by: Pixabay

Low Fluid Levels

The most frequent causes for this problem is the presence of low levels of fluid. The most commonly used fluid to test is the oil. An oil level that is low could cause severe damage to the engine. Check that other fluids, including brake fluid and coolant are in the right amount.

Blocked Fuel Filter

If your fuel filter is clogged this can cause your engine to fail and make it impossible for your car to reach speeds of 30 mph or more. It is important to replace your fuel filter at least every two years to ensure the highest performance of your car Therefore, ensure that you replace it on a regular basis in the course of routine maintenance.

Clogged Catalytic Converter

The catalytic converter reduces the harmful emissions that your vehicle emits by turning them to harmless ones. Blockages can impede airflow and cause an increase in power. This could be the reason your vehicle isn’t able to go more than 30 mph even with an engine check light illuminated. If that’s the scenario, you’ll need to replace the catalytic converter in order to bring back full performance.

Bad Mass Air Flow Sensor (MAF)

The sensor for mass air flow determines the amount of air that enters the engine, so that additional fuel can be added to ensure optimal performance. If the sensor malfunctions it can cause an increase in power. This could be the reason your vehicle won’t be able to go more than 30 mph when that check engine warning light turned on. It’s time for the replacement of MAF sensors in order to bring the engine back fully functioning.

Faulty Throttle Position Sensor (TPS)

The sensor for the throttle position tells the computer how wide it is open, or shut off the plate impacting the amount of fuel to the engine when it is in the process of combustion. If the sensor is damaged it can restrict the amount of power available, which could cause your car to not be able to reach speeds of 30mph and have the check engine light coming on. It’s necessary to replace the sensor to make sure your car is running smoothly again.

Transmission Issues

A transmission problem can lead to the loss of power that could be the reason your car can’t exceed 30 mph. A damaged clutch or fluid level that is low or a sensor that is not functioning properly are typical transmission problems. Check the dipstick of your car for proper fluid levels and make sure the clutch is securely in position. It’s also possible that your vehicle’s transmission control module is not functioning properly. It’s important to test the sensors to ensure they’re working correctly.

Car Wont Go Over 30MPH With No Check Engine Light

If your vehicle isn’t going over 30 mph, and there’s no check engine indicator on the dashboard, it could be because of many things.

Car Wont Go Over 20 - 30 MPH
Photo by: Pixabay

Bad Spark Plugs

One of the main reasons for a car not speeding over 30mph is the problem with spark plugs. If the spark plugs in your car are damaged or worn out they will not be able to generate the spark needed to ignite, resulting in an engine that isn’t as powerful.

To determine if this could be the problem in your car take off every spark plug and examine it for evidence of damage. If you notice that any of them requires replacing, ensure to replace them all at once.

Failing Clutch

Another reason that could be the cause for your vehicle not reaching 30 mph is a failed clutch. The clutch transfer force from the motor to the transmission which allows the wheels to turn, propelling the car ahead.

If your clutch is experiencing issues, it may hinder power transfer correctly and cause your vehicle to slow down. To identify the issue make sure you take your car to an examination and have a professional examine for the health of the clutch system.

Blocked Air Filter

An air filter that is blocked could also cause problems with acceleration and speed in vehicles. The role of the air filter is to eliminate dust dirt, dirt and other contaminants out of the air that is entering the engine. When it gets blocked the air flow can be restricted into the engine, which can result in slow performance when operating at high speeds.

To address this problem, lift the hood and examine (or substitute) your air filters yourself. It is also possible to bring it to a professional who will fix it swiftly and conveniently.

Dirty Fuel Injectors

In addition the fuel injectors that are dirty are another frequent reason for cars that cannot go beyond 30mph, without warning lights flashing. Fuel injectors pump fuel directly into the combustion chamber which mixes with oxygen prior to being burned by spark plugs.

If the injectors get blocked or are corroded or corrosion, they won’t be able to pump enough fuel to an engine. This results in lower effectiveness when trying speed over 30mph. Make sure you check the fuel tank to ensure that it’s not empty. You might also require a tune-up if your vehicle isn’t accelerating properly.

Car Wont Go Over 30 MPH: FAQ

1. Why is my car struggling to accelerate past 30 mph?

If your car is having trouble accelerating past 30 mph, there could be a number of things causing this issue. One common cause is a clogged fuel filter. A dirty fuel filter can restrict the flow of fuel to the engine, causing it to struggle to reach higher speeds. Another possible cause could be a problem with the transmission, such as low transmission fluid or a faulty sensor. It is recommended to get your car to a mechanic to diagnose and fix the issue.

2. What can cause my car to not accelerate properly?

There are several potential causes for your car not accelerating properly. One common cause is a malfunctioning mass air flow sensor or oxygen sensor. These sensors provide important data to the engine control unit (ECU) to determine the correct air-fuel mixture for combustion. If they are not functioning correctly, it can affect the car’s ability to accelerate. Other possible causes include a clogged fuel injector, a problem with the ignition system, or a dirty air filter. It is best to have a professional mechanic diagnose the issue.

3. What should I do if my car wont go over 30 mph?

If your car wont go over 30 mph, it indicates a problem with the engine or drivetrain. First, you can try to accelerate gradually and see if the car responds. If not, it is recommended to bring the car to a mechanic as soon as possible. Driving in this condition could further damage the vehicle. The mechanic will be able to diagnose the issue and provide the necessary repairs.

4. Why won’t my car accelerate when I press the gas pedal?

If your car does not accelerate when you press the gas pedal, it could be due to a number of reasons. One possibility is a malfunctioning throttle position sensor (TPS). This sensor communicates with the ECU and tells it how far the accelerator pedal is pressed. If it is faulty, the ECU may not receive the correct signal, resulting in a lack of acceleration. Another possible cause could be a problem with the fuel system, such as a clogged fuel line or a faulty fuel pump. It is recommended to have a professional mechanic inspect the car to determine the exact cause of the issue.

5. What could be the potential causes of my car not going over 30 mph?

There are several potential causes for a car not going over 30 mph. Some common causes include a clogged catalytic converter, a misfiring engine, or a problem with the ignition system. Other possible cause could be a dirty fuel filter.


In conclusion, there are several possible reasons why a car may not go over 20-30 mph. Firstly, it could be due to a problem with the fuel system, such as a clogged fuel filter or a malfunctioning fuel pump. These issues can restrict the flow of fuel to the engine, resulting in reduced power and acceleration.

Secondly, a faulty oxygen sensor or mass air flow sensor could also be causing the car’s limited speed. These sensors play crucial roles in regulating the air-fuel mixture in the engine. If they are not functioning properly, it can lead to an incorrect balance of fuel and air, affecting performance.

Lastly, mechanical problems like a worn-out transmission or slipping clutch may also be responsible for the issue at hand. A failing transmission can cause gears to shift improperly or not engage fully, limiting speed capabilities. Similarly, if the clutch is slipping or worn out, it will struggle to transfer power from the engine to the wheels effectively.

In summary, when facing an issue where your car wont go over 20 – 30 mph, it is essential to consider potential problems with the fuel system, oxygen sensor/mass air flow sensor malfunctions or mechanical failures like transmission issues or a slipping clutch. Identifying these underlying causes will help you address and resolve them promptly for improved performance on the road.

Similar Posts

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.