Why Is Your Car Not Accelerating Properly : Causes & Quick Fixes


A car not accelerating properly can be a really serious problem if you have been facing it for a long time. Most cars use internal combustion engines, which require flammable fuel to run.

Acceleration is given to the engine to increase the speed of the car. But sometimes the speed of the car does not increase when the acceleration pedal is pressed and the engine of the car does not accelerate, due to which a decrease in power and performance can be felt. There can be many reasons for this problem. In this post, we will learn in detail about the main reasons for the car not accelerate properly.

Why Is Your Car Not Accelerating – Causes

If your car is not accelerating properly, possible causes include a clogged air filter, a faulty MAF sensor, a faulty fuel filter, pump, or injector, a failed transmission system, stuck brakes, a failed TPS or oxygen sensor, a faulty ECM. , a faulty catalytic converter, or incorrect engine timing.

Let us know in detail the reasons for the car won’t accelerating.

1. Faulty Mass Air Flow Sensor (MAF)

MAF Sensor

The MAF sensor is located in any part of the air filter on a car’s diesel, gasoline, or hybrid engine, providing a signal to the ECM about the pressure and speed of clean air moving through the air manifold into the engine’s internal combustion chamber. Based on this signal, the ECM determines the proper fuel mixture and ignition timing for engine operation, thereby successfully completing the combustion process in the internal combustion chamber of the engine.

But a faulty or clogged MAF sensor is unable to send an accurate signal of air pressure and speed to the air intake system, causing the ECM to be unable to determine the proper air and fuel ratio in the fuel mixture, reducing engine power and performance. and acceleration problems arise.

2. Clogged Fuel Filter

bad fuel filter symptoms

Internal combustion engines require some type of fuel, due to which fuel combustion takes place in the internal combustion chamber of the engine, which starts the engine and provides power.

But sometimes, due to a faulty or clogged fuel filter, the engine does not get enough fuel as required, causing a reduction in engine power and performance. A faulty or clogged fuel filter can also be a major reason for a car not accelerating.

3. Faulty Fuel Pump

fuel pump

The function of the fuel pump in cars is to send fuel under high pressure to the fuel injector, due to which the fuel injector in the internal combustion chamber of the engine throws the fuel in the form of a spray on the piston with high pressure, and this fuel becomes more flammable, which makes the fuel combustion process easier and quicker.

But sometimes a faulty or weak fuel pump is unable to supply fuel with high pressure to the fuel injectors. Due to this, the fuel injector sprays a small amount of fuel onto the piston. Due to this, the engine starts having acceleration-related problems.

4. Faulty or Clogged Fuel Injectors

fuel injectors symptoms

The fuel injector is a vital part of any engine with an internal combustion chamber, fitting into the top of the engine. Fuel injectors inject fuel as a spray onto the piston, making the fuel more flammable, thereby completing the fuel combustion process and starting to deliver engine power and performance.

But faulty or clogged fuel injectors are not able to spray fuel with high pressure on the piston. Due to this, a decrease in the power performance of the engine may be felt. Faulty or clogged fuel injectors can be a major reason for a car not accelerating properly.

5. Accelerate Pedal Issue


Every vehicle is equipped with an accelerator pedal, and when pressed, the engine gets acceleration. Some vehicles are equipped with an electronic accelerator pedal, which works based on a sensor. But some vehicles have a simple accelerator pedal, in which a wire connects the accelerator pedal to the throttle body of the engine.

Many times, there is a problem with the accelerator pedal in vehicles. For example, there is a sensor or wiring-related fault in the electronic accelerator pedal, and the air actuator of the throttle body does not work even when the pedal is pressed due to a broken wire in the ordinary accelerator pedal, thereby causing difficulty in accelerating the engine. That is why the speed of the car does not increase, even due to a bad accelerator pedal.

6. Faulty ECM

faulty pcm

In vehicles, the ECM is the main part that controls every function of the engine and the entire vehicle. The ECM, also known as the Engine Control Module, controls the overall functioning of the engine.

The ECM prepares the firing sequence of the proper fuel mixture with the correct timing of the pistons based on signals from sensors in the engine and sets the proper ignition timing as required. But a bad ECM is unable to perform all these functions, along with the correct timing of engine starting. Therefore, a bad ECM can also cause problems with the car not accelerating.

7. Bad Throttle Position Sensor (TPS)

Throttle Position Sensor

The throttle body mounted on the vehicle’s engine works to control the acceleration of the engine, in which a (butterfly) actuator is installed to control the air, which opens and closes according to the pressure of the accelerator pedal. A throttle position sensor (TPS) is installed on the throttle body to sense the position of the actuator. Which sends a signal of the position of the throttle actuator to the ECM, based on which the ECM operates the fuel mixture and power supply with the correct timing as per the engine’s requirements.

But due to a bad throttle position sensor (TPS) or somehow loose wiring connection, the ECM does not receive the signal from the throttle position sensor (TPS). Due to this, the functioning of the ECM starts getting disrupted, due to which the car starts having acceleration problems. Sometimes, the engine RPM starts going up or down when idling.

8. Faulty Oxygen Sensor

oxygen sensor

The oxygen sensor analyzes the ratio of fuel and air burning in the engine. Generally, an engine with an internal combustion chamber requires a proper mixture of air and fuel to burn the fuel successfully, so that the engine can start smoothly and gain speed.

The oxygen sensor sends a signal to the ECM about the ratio of air and fuel used in the engine, and the ECM, based on signals from the oxygen sensor and other sensors, prepares the fuel mixture in the engine in the right amount and time, thereby allowing engine acceleration. Is able to pick up speed accordingly.

But a bad oxygen sensor is unable to send the correct information to the vehicle’s ECM. Due to this, there is a problem with increasing the speed of the car and even after pressing the accelerator pedal completely, the car is not able to accelerate properly.

9. Incorrect Timing Belt or Chain Setting

timing chain

Any engine consists of two parts with an internal combustion chamber. One is the engine block, in which the crank and piston move, and the other is the engine head, which consists of the air intake valves, exhaust valves, and camshafts as the main parts. The camshaft timing is set by a belt or chain according to the position of the engine crankshaft.

So that, according to the position of the piston in the engine, the intake air can come in and the exhaust gas can come out at the right time, this process is done by opening and closing the valves by the camshaft. Where the setting of the engine timing belt or chain plays an important role.

A damaged engine timing belt or chain can cause engine starting, misfires, and acceleration problems. Therefore, the incorrect setting of the timing belt or chain can be one of the main reasons for the car not accelerating.

10. Worn Clutch

worn clutch plate

Many vehicles have manual transmissions. In such transmissions, the clutch is used for starting, stopping, and gear shifting. The clutch stops or starts the continuous flow of power from the engine to the transmission as required by the driver.

The clutch assembly consists of a flywheel attached to the engine, which rotates continuously with the engine, and a clutch plate attached to the main shaft of the transmission. When the clutch is released, the clutch plate and the pressure plate stick together, and when the clutch is pressed, the clutch plate moves away from the flywheel.

Due to this, the clutch transfers or stops the power of the engine of the vehicle to the transmission as per the need of the driver, due to which the vehicle accelerates according to the prescribed gear.

But sometimes, due to excessive wear of the clutch or damage to the pressure plate, the clutch does not stick to the engine flywheel properly. Due to this, more slipping occurs between the engine flywheel and the clutch plate during engine acceleration. Due to this, the car is not able to hold speed properly during acceleration.

How To Fix Your Car Not Accelerating Properly?

If your car is having acceleration problems, all the causes of this problem have been explained to you in detail. You have to observe the reasons related to the acceleration of the car and the cause of any defect has to be rectified. so that the problem related to acceleration in your car can be eliminated. You can do these things to solve this type of problem.

  • Check MAF Sensor & Wiring: if the MAF sensor is bad, replace it with a new one or repair the broken MAF sensor wire.
  • Check Fuel Filter: If your vehicle’s fuel filter is clogged, then replace the fuel filter with a new one.
  • Check The Fuel Injectors: if the fuel injector is clogged or dirty, then clean the fuel injector. If necessary, replace the fuel injectors with new ones.
  • Check Fuel Pump Pressure: If the fuel pump shows low fuel pressure, then get the fuel pump repaired or replace the fuel pump with a new one.
  • Check Oxygen and TPS Sensor: If these sensors are damaged, replace them with new ones.
  • Check Vehicle’s ECM: If any fault is detected in ECM. Then get it repaired. Because replacing the ECM can be a costly option.
  • Check Catalytic Converter: Clean the clogged catalytic converter.
  • Check Clutch System: To test this, you drive the vehicle, then, after shifting to second gear, release the clutch completely and accelerate rapidly. If your vehicle has a clutch plate problem, the RPM of your engine will increase, but the speed of the vehicle will remain normal. These symptoms are caused by a bad clutch plate.

Car Struggling To Accelerate & Check Engine Light Coming On

If you are experiencing difficulty accelerating your car and the illuminated check engine light is on, this is a sign of a possible problem with the engine or related components. Typically, there are several engine-related components that can cause this problem, such as faulty sensors, clogged fuel injectors, or ignition system problems.

To resolve the problem, you should get your car diagnosed by a qualified mechanic with an OBD scanner and the appropriate equipment. So that further serious damage to the engine can be avoided.

My Car Won’t Accelerate When i Push The Gas

If your car is not accelerating when you press the gas pedal, common causes of this problem include a faulty throttle position sensor, clogged fuel injectors, or a bad air flow sensor. Additionally, problems with the fuel pump or clogged air filter can also hinder proper engine performance.

So if your vehicle is not accelerating properly, it is best to contact a qualified mechanic to diagnose and fix the specific problem, as driving with acceleration problems can potentially cause additional engine damage.

Why is Your Car Won’t Accelerate Past 40 MPH?

If your car is failing to accelerate above 40 mph, possible causes include a bad throttle position sensor, a clogged air filter, or a bad fuel pump. Additionally, transmission issues, a slipping clutch, or a faulty torque converter can also hinder your car’s acceleration, causing the car to fail to accelerate beyond 40 mph.

So whenever you are facing this problem in your vehicle, the first thing to do is to inspect the error codes, check the fuel delivery system, and check the transmission components.


Q. When I press the gas pedal it won’t accelerate?

The main cause of this type of problem in a car is a problem with the intake air system of the engine. Because oxygen is required for the combustion process in the internal combustion chamber of the engine, acceleration can be produced by the car’s action. Along with this, the fuel system could also be the reason.

Q. Can a bad transmission affect acceleration?

Yes, problems like a slipping clutch or a faulty torque converter can hinder acceleration. A worn clutch or faulty torque converter can cause slipping during acceleration or not engaging at all.

Q. What should I do if my car shows no acceleration and no error codes?

You should consult a qualified mechanic for a thorough inspection of your vehicle, as issues like a bad fuel pump or ignition system could be contributing to the problem.

Leave a Comment

error: Content is protected !!