Car engines use the air-fuel mixture and spark to produce power in the combustion chamber during the combustion process.
Then, the car engine transfers the generated energy to the transmission to move the wheels. This process continues with maximum effectiveness until you turn off the engine.
Sometimes, our car loses power while driving due to the malfunctioning of one or more system components. Whether your car loses power while driving and dies or it only has low power output, a technician can rectify the problem.
This article will discuss common causes of loss of power while driving and highlight probable solutions to the problem.
Understanding Power Loss in Cars
In the context of a car, losing power often refers to the vehicle’s inability to maintain speed, accelerate effectively, or respond promptly to the driver’s inputs.
The car’s power is generated by the engine, which combusts fuel to create a force that is then converted into motion by the transmission. If any part of this system is not working correctly, it can lead to a noticeable decrease in the car’s power.
How a Car’s Power System Works?
The power system primarily comprises the engine, transmission, drivetrain, and electrical system.
- Engine: The engine is essentially the heart of your vehicle. It burns fuel-air mixtures in its cylinders and transforms this energy into mechanical force. This is primarily achieved through internal combustion, where the engine converts the energy released from burning fuel and air into rotational force, which turns the engine’s crankshaft.
- Transmission: This mechanical force, or torque, is then transferred to the transmission. The transmission is like a multi-speed bicycle: it changes the gear ratio between the engine and wheels, ensuring the engine operates at an efficient speed whether you’re accelerating, cruising, or climbing steep hills.
- Drivetrain: The drivetrain transmits power from the transmission to the wheels. Different types of drivetrains include front-wheel drive (FWD), rear-wheel drive (RWD), all-wheel drive (AWD), and four-wheel drive (4WD).
- Electrical System: The car’s electrical system includes the battery, alternator, and starter. The battery supplies electrical energy to the starter to start the engine. The alternator then produces electricity to power all electronic components, including lights, radio, and air conditioning, and to recharge the battery.
Common Symptoms of a Car Losing Power
These symptoms can manifest in various forms, each pointing to potential trouble within your vehicle’s power system.
#1. Difficulty Accelerating.
You might press the gas pedal and find the vehicle doesn’t pick up speed as it usually does, or it might take noticeably longer to reach a particular speed.
This issue could point to a range of problems, including a clogged fuel line, failing spark plugs, a malfunctioning mass airflow sensor, or a slipping transmission.
#2. Frequent Stalling.
If your car stalls frequently, particularly during acceleration, this could indicate that it’s not getting the power it needs. Stalling can happen due to fuel delivery problems, electrical issues, or problems with the ignition system.
#3. Inconsistent Engine Performance.
The vehicle might run smoothly one moment and suddenly start jerking or surging the next.
The engine might also misfire, which happens when the engine’s air-fuel mixture doesn’t ignite correctly in one or more cylinders. This can cause power loss and irregular engine performance.
#4. Increased Fuel Consumption.
Higher fuel consumption can result from the engine overworking due to underlying problems, such as worn-out spark plugs, a malfunctioning oxygen sensor, or a leaking fuel injector.
#5. Unusual Noises.
Cars communicate their condition through sounds. If you hear unusual noises—like rattling, knocking, or hissing—coming from the engine, it could indicate that your vehicle is losing power.
These sounds might indicate issues such as a loose or cracked component, a clogged catalytic converter, or engine detonation.
#6. Warning Lights on Dashboard.
If your vehicle loses power, you might see the check engine light, the oil pressure light, or the battery light turn on, among others. Each light corresponds to a specific system in the vehicle, and their illumination suggests a malfunction in the respective system.
What Causes Car Loses Power While Driving?
A vehicle engine is a fine-tuned machine with several car sensors and components that works in harmony to produce optimal performance. If any of these sensors or components dies, it’ll alter the overall engine performance.
Therefore, a loss of engine power is a real-time problem and indicates a system malfunction. Here are probable causes of loss of power in a vehicle.
#1. Faulty fuel injectors.
Fuel injectors perform a vital role in the optimal engine operation. However, if the fuel injectors fail or leak, they will not provide adequate gas to the combustion chamber, especially on higher revs.
Aside from the loss of engine power, faulty fuel injectors can cause other problems like engine misfiring, rough idling, and engine hesitation or stalling. Also, if there’s a gas leak, you’ll perceive a gas smell around the injectors.
#2. Clogged catalytic converter.
The catalytic converter is an essential exhaust system component that converts harmful gas into less harmful emissions before releasing them into the atmosphere. So, if your car loses power or runs slowly, it could mean you have a clogged catalytic converter.
If the catalytic converter clogs or blocks, it’ll block the exhaust gases from getting out of the car. This will lead to a loss of engine power and overall poor performance.
#3. Engine/exhaust backfire.
An incorrect air-fuel mixture ratio is the primary cause of exhaust backfires. It is a small explosion with a loud bang or pop from the exhaust tailpipe. In some situations, a burst of flame will come out of the exhaust tailpipes.
Exhaust backfires can be caused by a bad MAP, MAF, IAT, fuel pump, fuel tanks in the gas tank, or issues with the injector or carburetor.
#4. Blocked diesel particulate filter.
Automakers design the diesel particulate filter (DPF) to filter diesel fuels in diesel engines. However, like other filters, as the DPF filters the diesel particulates, it can get clogged and prevent adequate fuel passage.
If this happens, your car may switch to limp mode. This mode will restrict your vehicle’s performance. The vehicle will not shift to higher gears until you fix the underlying problem.
#5. Low compression.
For an engine to provide optimum performance there must be proper cylinder compression during the combustion process. If the vehicle has low compression, there will be low power output.
So, if your car loses power while driving and jerks, low engine compression can be the culprit. However, there could be many causes. So, don’t conclude yet until a thorough diagnosis proves the cause.
#6. Bad air filters.
A vehicle engine requires an adequate air-fuel mixture ratio for a complete combustion cycle in the combustion chamber.
Therefore, the air will pass through an air filter before entering the manifold for mixing purposes. This component prevents dirt, bugs, debris, and other contaminants from getting into the engine.
As the air filters prevent these contaminants from damaging the engine, these impurities build up and clog the air filter over time. When the filter gets clogged, the engine will suffer insufficient air, causing low power output.
#7. A malfunctioning camshaft position sensor.
The camshaft position sensor monitors the rotating speed of the camshafts and sends the readings to the powertrain control module (PCM).
The PCM is also known as the brain of the car. However, it is primarily called a car computer. Once the car computer receives readings from the camshaft sensor, it uses the data to monitor and control the ignition and fuel injection.
If the camshaft sensor sends inaccurate data to the powertrain control module, it’ll affect the overall fuel injection and ignition. Of course, compromised fuel delivery and ignition will cause low power output or loss of engine power.
#8. Faulty oxygen sensor.
The oxygen sensor monitors and measures the exhaust byproducts that leave the engine after each combustion cycle.
After that, it sends this information to the car computer. The computer uses this data to re-determine the real-time air-fuel ratio that gets into the combustion chamber.
The oxygen sensor is mounted on the exhaust pipes. It assists the fuel injection system and the engine timing in doing their jobs accordingly. It also helps in emission control.
Unfortunately, if this sensor fails or malfunctions, it’ll send false readings to the car computer.
As a result, the car computer will not know the real-time air-fuel ratio entering the combustion chamber. And this will cause the car to lose power when driving uphill or downhill.
#9. Malfunctioning MAF sensor.
Several sensors monitor the air-fuel mixture ratio in vehicles. This shows the importance of a proper air-fuel ratio in a vehicle.
The mass airflow sensor is one of those sensors. It measures the volume of air entering the engine and signals the engine control unit. The engine control unit uses this data to calculate the engine load.
So, if this sensor fails, it may result in a car losing power and juddering.
#10. Defective fuel pump.
The fuel pump is one of the most important fuel system components. It is housed inside the gas tank. The fuel pump draws fuel from the gas tank and exports it to the injectors.
If the pump fails, it can cause several drivability issues. For example, if your car loses all power while driving and won’t start, it could be you have a bad fuel pump that is not sending gas to the injectors.
#11. Lousy spark plugs.
A gasoline engine will not start without spark plugs. The plugs ignite the air-fuel mixture into the combustion chamber by transmitting an electrical current from the ignition coils.
Therefore, the engine will suffer if the plugs die and won’t transmit the electrical current properly. It’ll only cause engine misfire or rough idling in the initial stage. If you ignore it for an extended period, it’ll worsen and cause starting issues.
#12. Lousy ignition coils.
The ignition coil is an essential ignition system component that converts 12 volts from the car battery to the 20,000 volts needed to start the engine.
If one or more of your spark plugs are not working properly, it’ll not provide enough power needed to burn the air-fuel mixture in the combustion chamber.
This means you won’t get the desired result when you depress the gas pedal. There are several causes of unresponsive gas pedals, but the common ones are defective EGR valves, failing turbos, and bad injector pumps.
Regardless of the cause, always run a thorough inspection and fix the cause of the power loss. If you ignore this lousy ignition for an extended period, it’ll cause severe catastrophe to the engine’s overall performance.
How Can I Restore The Power In My Car?
There are many reasons why your vehicle may lose power – here is what to look out for and what to do next.
#1. Spark plugs.
Over time, spark plugs can lose their effectiveness in powering the engine – and will either need to be repaired or replaced.
You will notice that there will also be a rattling sound and soon you will not be able to start the engine.
#2. DPF filter.
A Diesel Particulate Filter (DPF) is designed to remove matter and exhaust pollutant particles when driving.
However, over a period of time they can become blocked – forcing your vehicle to enter ‘limp-home mode’. This is where your vehicle will have very little power output. It stops further damage to other parts of the vehicle.
You can avoid this issue by driving on the motorway at the speed limit for more than 30 minutes. This is known as passive regeneration and can help burn off excess soot in the filter.
Some vehicle’s use active regeneration where extra fuel is injected to raise the temperature in the filters.
If neither of these work, then you’ll need to visit your local garage and have a ‘forced regeneration’ of the DPF.
#3. Air/fuel filters.
Vehicles have their own air and fuel filters to help protect the quality of the air and fuel – and keep dirt particles out of the engine.
If the filters are worn or dirty, it can disrupt the air or fuel flow and result in a loss of power. In most cases, a filter replacement will be necessary to rectify the problem.
#4. ECU.
The Engine Control Unit (ECU) can sometimes give false readings which will cause the engine to lose power.
In other cases, it can cause the vehicle to come to a complete stop. This is because the ECU’s programming believes that there is a serious issue with the car.
Park somewhere safe, turn off the engine and let it cool down. Restart the engine and see if the same issue persists. If so, you may need to contact a garage or local mechanic.
There are several other reasons why the ECU is having issues. Knowing what your car dashboard warning lights mean can be helpful.
#5. Exhaust.
If your exhaust is blocked or damaged then your vehicle will immediately lose power. However, a backfiring exhaust happens when there is an incorrect ration of fuel to air within the vehicle. You will hear a loud pop or bang coming from the rear of the vehicle.
This is something that could lead to more serious damage to your car, so take your vehicle to a mechanic as soon as possible.
#6. Gears and clutch.
If your gears are slipping, then it will lead to the vehicle’s power being impacted. This is because the engine’s output fails to reach the wheels effectively.
Clutch or gear slipping should be dealt with by a local garage that can get a greater understanding of why it has happened and what to do next.
#7. Sensors.
In modern vehicles, there are many sensors for different purposes. If there is an issue with them or the information that they are feeding back to the ECU is incorrect, it could lead to the vehicle having less power.
This is typical with a Mass Air Flow (MAF) sensor, which monitors the air intake to the throttle when accelerating.
#8. Fuel injectors.
When an engine is turned on, the fuel injectors send fuel into the combustion engine. If there is a lack of pressure, then an incorrect amount of fuel will be added – creating a lack of power.
Worryingly, it will also lead to other issues in the engine that can be very costly. This is a technical job and should only be carried out by a qualified mechanic.
#9. Catalytic converter.
Responsible for controlling the emissions that leave the car’s exhaust system, a catalytic converter can become clogged over time, leading to a lack of power and acceleration.
They are popular for thieves, so protect your catalytic converter today. The first sign there is a blockage is a lack of power – however, if the issue isn’t resolved quickly then it can lead to a total engine failure.
#10. Air conditioner.
Although this is more common in older vehicles, on a hot summer day, you may be using the air conditioner. However, if it isn’t in top working order, then it can start draining power from other parts of the vehicle.
A re-gas might help with this – but it might just be a side effect of a day with high temperatures.
#11. Turbocharger.
Once only found in sports cars, turbochargers are now a common sight in modern vehicles due to the performance and fuel economy benefits they provide.
The turbocharger works by increasing the air pressure in a combustion engine, which allows more fuel to be added into the mix. This then creates extra power when accelerating.
However, when they have a problem, they work in the opposite way and cause a drag on power. This can range from having dirt and debris in the turbocharger, to a loose connection, to having major damage to the unit or the connectors.
They also need to have the right oil and filters attached to work properly. As there are more specialized in how they work and they are worked on, it is advisable to take your car to a mechanic to get any issues with your turbocharger fixed.
#12. Wear and tear.
Like many other parts of a vehicle, over time and many trips on the road, parts of the engine can wear down – which can sometimes lead to problems. Regular car servicing will help with this, along with any suggestions at the annual MOT.
How to Prevent Engine Power Loss?
Although completely avoiding engine faults is not possible, but there are different measures you can take to minimize the chances of experiencing decreased performance and power.
By implementing certain practices, you can effectively decrease the possibility of encountering such issues.
Here are some essential steps to maintain your car’s power and performance:
- Follow the manufacturer’s guidelines and get your car serviced at least once a year.
- Use Redex fuel additives to keep the fuel system clean and prevent blockages caused by dirt and deposits.
- Address any dips in performance promptly. The sooner you fix a problem, the less long-term damage it can cause.
- Regularly check the air filter for blockages and buildup. Conducting small checks yourself can be beneficial in the long run.
- Stay attentive to the general condition of the engine, including regular inspections of coolant/antifreeze levels and oil.
FAQs.
Q: Why does my car have no power when I accelerate?
A loss of engine power is usually caused by malfunctions in the mechanical and electrical engine components. Sometimes you can rectify these problems by changing the spark plugs, cleaning the distributor rotor, or cleaning the MAF sensor.
Here are the mechanical problems that could cause a loss of engine power when accelerating;
- Foul spark plugs
- Low engine compression
- Clogged air filter
Here are the electrical components that could be the culprit;
- Lousy O2 sensor
- Defective MAF sensor
- Bad MAP sensor
- Faulty camshaft position sensors
- Ignition coil issues
Lastly, one of these fuel system and exhaust issues could be the culprit;
- Bad fuel pumps
- Clogged fuel filters
- Lousy injectors
- Clogged exhaust pipes.
Q: How do I know when my fuel pump is bad?
The importance of a fuel pump in a vehicle cannot be overemphasized. Without it, a vehicle will not start. Thankfully, it shows several symptoms when it starts failing to notify the driver to change it on time.
A failing fuel pump will show one or more symptoms before it finally stops working.
- Whining noise from the gas tank
- Engine sputtering
- Engine stalling at high temperature
- Car surging
- Loss of engine power
- Poor gas mileage
- Hard starting
- The car won’t start. This happens when the fuel pump is long gone.
Q: Why do cars lose HP over time?
Every vehicle engine loses power over time due to friction and wear and tear on various engine components. However, a car engine loses power because of one of the following factors: improper combustion, low compression, or inappropriate air-fuel mixture ratio.
As we explained above, your vehicle engine needs an adequate air-fuel ratio for optimum performance. If the air filter clogs, it’ll restrict adequate airflow to the engine. This will suffer the combustion process.
Secondly, if the exhaust pipe clogs, thereby restricting the exportation of exhaust byproducts, it’ll lose engine horsepower.
Q: Why is my car juddering and losing power?
Fouled or faulty spark plugs are the common cause of car juddering. In addition, a blocked air filter and injection system problems can send an obscene amount of air and fuel into the combustion chamber, causing the car to stutter or judder.
After covering thousands of miles with the vehicle, the internal engine components will suffer wear and tear. In addition, the valves and other engine components may get clogged with sludge.
If the juddering and loss of power only occur on idle, you may have a worn-out car sensor like a camshaft sensor or a small fuel leak on the engine vacuum.
Q: Do cars lose torque?
The Pistons in the engine cylinder walls generate torque as they reciprocate up and down on the crankshaft. Now, do cars lose this torque?
Wear can reduce vehicle torque and horsepower. Here’s what you need to know. There’s no doubt; that wear and tear will run your engine down. There will be a loss of torque, horsepower, and bad gas mileage due to wear and tear.
Q: Can a bad transmission cause power loss?
Yes, in some cases, a bad transmission can cause power loss. If you’re driving and the vehicle is revving pretty fine, but there’s poor acceleration, it’s a symptom of a transmission failure.
However, there are several other causes. First, inspect the vehicle properly before drawing a conclusion.
Final words
You’ve learned why your car loses power while driving and ways to restore engine power. At this juncture, you won’t ask, ‘Why does my car have no power when I accelerate?’ because we’ve outlined the probable reasons.
However, contact your mechanic if you don’t trust your guts and you’re not comfortable diagnosing a car that won’t accelerate. He’ll run a professional diagnosis and fix the problems.