Why Won’t My Car Accelerate? (11 Reasons Why)

Your car won’t accelerate. Did you push the gas pedal too hard? Did you forget to put the key in the ignition? Is it leaking something into the fuel system?

One of the most crucial elements of driving is acceleration. Therefore, a driver must understand what causes speeding issues so that their vehicles stimulate smoothly. I will help you get the answer you need about why your car won’t accelerate evenly!

Why Won’t My Car Accelerate?

1. Mass Air Flow Sensor Bug

Your mass air flow sensor is located at the front of the throttle body and is liable for controlling how much air goes into the engine.

Meanwhile, if too much fuel enters the engine, it would create more pressure inside the engine and cause it to burn hotter than usual.

As a result, if this sensor fails, it will not be able to require the engine when to start and when it has reached maximum power!

2. Obstructed Fuel Filter

Your car’s gasoline filter is the first component to become clogged while maintaining peak performance.

When you’re driving, the fuel filter traps these impurities, which can cause your car to slow down.

Overall, if there’s too much material in the filter, it will sit at a higher level than necessary, which means your air-fuel mix will be much denser than what’s needed for the car’s acceleration!

3. Blocked Exhaust Pipe

If the exhaust gases can’t exit the vehicle through the tailpipe, there won’t be enough space for fresh air to enter the combustion chambers, which will prevent the engine from starting.

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Furthermore, these blockages cause the vehicle to stall and progressively leak smoke inside. As a result, it can no longer exhaust fresh air and eventually stops working.

Therefore, you’ll notice that your car doesn’t accelerate as fast as usual and would make the vehicle drive slowly when attempting to accelerate, weakening the engine’s functionality!

4. Defective Oxygen Sensor

A defective oxygen sensor causes the powertrain to get incorrect messages.

As a result, inadequate balance leads to incomplete combustion, which obstructs power transfer to the car’s mechanical components.

As well as that, while a catalytic converter might clog up, the oxygen sensor can also contribute to poor engine performance.

In the event that they become clogged and malfunction with time, it can cause unpredictable idle, poor acceleration, and failed emissions tests.

Undoubtedly, the engine would start to function poorly, ultimately harming the environment!

5. Unreliable Fuel Injectors

Unreliable Fuel Injectors

Your fuel injectors use a regulator to determine the proper pressure before delivering gasoline into the cylinders of your car. For the spark plugs to ignite the fuel, it is then sprayed into the combustion chamber.

Under these circumstances, when you press the gas, the fuel injectors likewise shoot fuel into the engine. At the same time, slow acceleration indicates that the car’s engine is running low on power.

Above all, these injectors are responsible for sending fuel into the engine and causing it to work properly. If they’re not functioning adequately, your car may be unable to keep up with your needs!

6. Low-Level Compression

A leak in one or more of the cylinders brought on by typical engine wear and tear is what causes compression loss.

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Additionally, compression loss in one engine cylinder may cause poor vehicle performance and misfire. Therefore, a decrease in power output signals internal component wear.

Generally, if the compression is low, the engine’s power will be poor, and the car won’t have enough potential to accelerate!

7. Damaged Fuel Pump

Through fuel lines, fuel pumps transport fuel from the gas tank to the engine.

However, an unreliable fuel pump could overheat and provide insufficient gasoline to the engine, leading it to run hot and shut off while traveling.

Basically, defective fuel pumps can lead to poor acceleration, and inadequate airflow can also prevent the engine from accelerating sufficiently!

8. Cracked Spark Plugs

A cracked spark plug is a result of the combustion process in your engine, and it can be caused by either an internal or external failure.

At this point, an internal failure occurs, which causes cracks in the electrodes that make up the spark plug.

As you can see, if you notice that your car doesn’t seem to be picking up speed when you push down on the accelerator, it could be because of fractured plugs!

9. Malfunctioning Camshaft Position Sensor

An electrical device called a camshaft position sensor monitors the position and transmits that information to the vehicle’s engine control module (ECM).

Moreover, this information is required by the ECM to regulate the spark’s timing and the amount of fuel allowed to enter the combustion chamber.

As an outcome, when these sensors fail, the engine’s performance will be significantly flawed, and you won’t be able to speed up, especially on roadways and highways!

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10. Busted Ignition Coil

Under intense heat and vibration conditions, the insulating material may break down, resulting in internal coil failure.

As well as that, because worn secondary ignition components like spark plugs increase the coil’s workload and voltage requirements, they can significantly reduce the coil’s useful life.

As an effect, if your ignition coil is busted, it prevents your car from getting enough power from its engine and causes it to stall out or not start at all!

11. Faulty Air Filter

Air filters are designed to keep dirt and debris out of the engine but also impact performance by restricting airflow down through the engine.

That is why the amount of air that can enter the internal combustion chamber will be restricted once an air filter becomes clogged.

By all means, the engine won’t be able to provide enough power to keep the vehicle running due to obstructed air filters!

To know more, you can also read our posts on why your car is cranking but not starting, why your car won’t jumpstart, and why your transmission fluid is brown


Car performance is a complex issue. It involves many factors, including the car’s engine, transmission, exhaust system, and other components.

As demonstrated, cars’ most frequent causes of slow acceleration are a mass air flow sensor bug, a clogged fuel filter, and a blocked exhaust pipe.

Ultimately, you will encounter sluggish accelerations if one of these components malfunctions, so better keep an eye on your engine peripherals!

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