What Can Cause Hesitation When Accelerating? 6 Common Causes

If you are a regular user of vehicles, then you must be well acquainted with a problem that almost every car user encounters. It is a situation in which you feel that as you try to accelerate the car it sometimes chokes and jerks or the engine experiences a slight hesitation and there is a disruption in the speed and movement of the car.

In this article, we will try to explain what can cause hesitation when accelerating the car.

What is Engine Hesitation?

When you try to accelerate, the car jerks and has problems gaining momentum. It’s when your car seems to lack power, stumbles or it misfires every time you step on the gas pedal/accelerator. This can make it quite difficult to keep moving and almost impossible to drive.

Sometimes the issue is not big and can be fixed easily, but the underlying cause of the problem may potentially damage other components and systems of the engine. So, one definitely would want to figure out why this is happening and get to the bottom of the issue and try to fix the problem without wasting time.

Causes of Engine Hesitation

We might think that since it is a common problem there may be a simple solution or answer to what can cause hesitation when accelerating the car. Unfortunately, there is no single solution in connection to this issue. There are a number of reasons that may be responsible for the car experiencing jerks or engine hesitation when accelerating.

The below-mentioned reasons are some of the causes of this problem:

1. A problem with the circuits

Every electronic device such as models and sensors that direct the vehicle engine is connected to each other via circuits. If there are any damaged wires or loose connections, they may prevent these circuits from functioning properly and result in jerks or engine hesitation.

2. A problem with the Ignition system

A vehicle’s ignition system is responsible for the ignition of the air-fuel mixture in the engine of the vehicle to generate the energy required to thrust your car on the road. When there is a problem with this system it will cause the engine to lose power inconsistently and the engine misfires resulting in hesitation under load. The most common causes of this include:

• Impaired or worn-out spark plug wires
• The bad Ignition control module
• Damaged ignition coil
• A problem with the distributor
• Worn-out spark plugs

All of these cause the engine to lose power and contribute to engine hesitation.

3. Vacuum Leaks

This is a situation where unmetered air passes into the engine, thereby leaning out the air-fuel mixture. This may be caused by a leaking, damaged, or worn-out vacuum hose or a damaged intake manifold gasket. The vehicle in such a case will encounter engine hesitation which is most evident at RPM. You will have to repair or replace the vacuum hose causing the leak.

4. Sensor problems

There are many different sensors that can cause the engine of the vehicle to misfire, causing hesitation when accelerating.  A few examples of these sensors are:

• Bad throttle position (TP) sensor– It monitors the position of the throttle valve and communicates the information to the engine control unit helping to maintain proper air-fuel mixture while the vehicle is being used. If there is a fault in this sensor the engine control unit fails to maintain the correct balance of the mixture required. So, it should be replaced immediately.
• Failed manifold absolute pressure (MAP) sensor– This sensor is used in the internal combustion engine ‘s electronic control system. The MAP provides prompt manifold pressure information to the engine electronic control unit (ECU). This information is then used to calculate the air density and regulate the air-mass flow rate of the engine, which then controls the required fuel for efficient combustion and affects the ignition timing. If this sensor is not working properly or is faulty then the engine control Unit (ECU) will not be able to gauge the amount of fuel needed to inject into the engine to accommodate the engine load.
• Damaged faulty mass airflow (MAF) sensor- This is a device in the throttle body that aids the engine computer to regulate the appropriate air-fuel mixture by determining the mass of air flowing through it. These sensors measure the air mass running into the engine intake. This is vital for the calculation of the amount of fuel needed to obtain the proper air-fuel ratio (AFR).

In simple words, when the external air flows into the engine as part of combustion the MAF measures the amount of air entering, this aids the engine control unit to regulate the amount of fuel needed to inject into the chamber. If these sensors are faulty or not working properly then there will be a problem as the required amount of fuel will not be injected causing hesitation. The car/ vehicle may encounter issues during driving like jerking, engine stalling and hesitation during acceleration. This can happen absolutely anywhere while speeding on a highway or just driving down a street and may lead to precarious situations.

• Faulty oxygen sensor- An oxygen sensor also known as an O2 sensor checks the amount of unburned oxygen present in the exhaust as it exits the engine. By doing so, this sensor provides a means for measuring the fuel mixture. With this information, the engine control unit can detect if there is too little or too much oxygen being ignited. In case the oxygen sensor is not working properly, the correct air-fuel mixture cannot be obtained. Also, it may run irregularly and will sound rough when it idles. This can affect the engine’s combustion intervals, timing, and other important functions. A bad O2 sensor can no longer generate accurate fuel injection levels, control exhaust gas or even warrant efficient fuel combustion. This can cause the vehicle to release unsafe environmental pollutants or carbon-based compounds.

5. Control module issues

A vehicle’s engine sensors provide the information to the PCM. The PCM utilizes this information or data to control all the output devices like fuel injectors and ignition coils. If there is a problem with the PCM then the vehicle may encounter hesitation while accelerating. But this is a very unusual problem. Mostly when this module is not functioning it may be due to a software updating issue and rarely an internal hardware failure.

6. Issues with other engine Management systems and Components

There are a few more components that may be responsible for what can cause hesitation when accelerating:

• Faults in variable valve timing (VVT) System
• Problems with exhaust gas circulation (EGR) system
• Issues with Throttle body
• Excessive exhaust back pressure (usually caused by a congested catalytic converter).

The above are some of the reasons for what can cause hesitation when accelerating.

The Bottom Line

We have discussed in this article some of the most common reasons for what can cause hesitation when accelerating your car. If your car is experiencing a hesitation problem or is sluggish, inspect your car for the above systems to solve the issue. However, if the issue persists, you must take your car to an experienced automobile workshop.