When you’re all set to rule the road, it can be annoying if your engine starts hesitating and loses power. Typically, it’s a sign that your car engine isn’t functioning properly. There are numerous reasons why a car hesitates on takeoff and fails to accelerate in time.
Your car can hesitate while taking off due to a bad fuel pump, dirty fuel injectors, clogged fuel filters, or faulty ignition. Malfunctioning sensors such as the throttle position sensor, mass air flow sensor, manifold absolute pressure sensor, or oxygen sensor can also be the reason.
Read on to learn why your car is lagging while taking off and what are the easy ways to fix it.
Why Does My Car Hesitate on Takeoff? – How to Fix
There are several reasons that can cause your car engine to hesitate on takeoff. Here, I have discussed them in detail, with their potential fixes.
| Cause of the Issue | Possible Fix |
| Bad Fuel Pump | Get the fuel pump replaced by a certified mechanic |
| Dirty Fuel Injectors | Remove and clean the fuel injectors with a suitable cleaner |
| Clogged Fuel Filters | Take out the dirty filter and clean it thoroughly |
| Faulty Ignition | Diagnose the faulty part of the system and replace it |
| Malfunctioning Throttle Position Sensor (TPS) | Reset the malfunctioning sensor first. If the problem persists, replace the TPS |
| Mass Air Flow (MAF) Sensor Issue | Clean the dirty sensor with a suitable MAF sensor cleaner. If this doesn’t fix the problem, you need to replace the MAF sensor |
| Bad Manifold Absolute Pressure (MAP) Sensor | Install a new MAP sensor |
| Faulty Oxygen Sensor | Get the oxygen sensor replaced by a professional mechanic |
Bad Fuel Pump
To deliver the necessary fuel to start your car, the fuel pumps work consistently. If the fuel pump is failing or not functioning correctly, your car won’t get sufficient fuel to take off, causing a few seconds of lag.
Also, a bad fuel pump allows contaminants to get into the fuel system. Contaminated fuel doesn’t allow the fuel system components to act instantly when you turn on the ignition.
How to Fix?
If the fuel pump goes bad, you will also see symptoms like car stall, difficulty in starting, loud whining sound from the fuel tank, etc.
If so happens, get your fuel tank replaced by a professional mechanic. Replacing the fuel tank will cost around $500 for the pump itself. The labor cost can reach up to $500.
Dirty Fuel Injectors
As the name implies, fuel injectors spray a mist of engine fuel into the engine cylinders. Over time, these injectors become dirty or clogged.
When the injectors are clogged by carbon residue and other contaminants, they start to wear, leading to fuel injector failure. It often leads to an improper mixture of air and fuel, causing the car to hesitate on takeoff.
If your car’s fuel injectors are dirty, you’ll notice symptoms like rough idling, engine misfires, rich fuel smell, and reduced fuel economy. The check engine light might also turn on.
How to Fix?
To easily get your car’s fuel injectors functioning optimally, you need to remove the dirty injectors and thoroughly clean them. For this:
- First, you need to remove the dirty fuel injectors. Depending on the type of engine, you’ll have to cut the fuel supply and take off the fuel rails. Refer to your owner’s manual for the proper removal process.
- Remove the O-rings and use a rubber hose to seal the opening so that the cleaner doesn’t escape. Now we need to arrange an electricity source to let the cleaner pass through the fuel injectors.
- Take an electric lead and connect one side to your car battery’s positive terminal. Link the other side to the fuel injector.
- Choose a suitable cleaner and attach it to the rubber hose. Flow the cleaner through the dirty injectors, and it will come out in the opposite way.
- Keep the cleaner flowing until the injector is spraying evenly. When you’re done, attach a new O-ring and place the fuel injector in its place.
Clogged Fuel Filters
Before the fuel enters the engine, fuel filters trap any contaminants that might be present in the fuel. If you don’t clean the fuel filters regularly, they can clog and restrict the flow of fuel to the engine.
Reduced fuel supply eventually results in a lean air-fuel mixture, causing hesitation during acceleration. Symptoms of clogged fuel filters include unusual noises from the fuel pump, difficulty starting, engine stalling, and failed fuel system components.
How to Fix?
Getting rid of this issue is easy. You clean the clogged fuel filters and maintain them regularly. Here’s how to clean dirty fuel filters:
- Depending on the make and manufacturing year of your vehicle, the fuel filters can be located near the fuel tank or engine. Before you start, disconnect the car battery.
- To relieve fuel pressure, disconnect the fuel pump fuse and run your car engine until it stalls. Now, detach the fuel lines and remove any clips or fasteners holding the fuel lines in place. You’ll need a wrench as well to separate the lines.
- After that, you need to take out the fuel filters. Use the necessary tools to remove any brackets or bolts. Once you get the filters in hand, spray a suitable carburetor cleaner to thoroughly clean them. When you’re done, reinstall the fuel filters.
Faulty Ignition
One common reason why cars hesitate during takeoff is faulty ignition. The ignition system of your car generates sparks when you turn on the switch to ignite the air-fuel mixture inside your car engine’s cylinders.
To complete the process, several components of the ignition system work together. When any of these components start malfunctioning, it results in car hesitation.
The symptoms of a faulty ignition will vary depending on which part of the ignition has gone bad. However, some general signs include an illuminated check engine light, backfiring, poor acceleration, and loss of power. In some cases, the vehicle might not start at all.
How to Fix?
As the ignition system features many different components, locating the faulty part is difficult. It can be the spark plugs, rotors, plug coil, ignition control module (ICM), worn key, or the ignition switch itself.
So, we recommend taking your vehicle to an expert mechanic to diagnose the faulty part and replace it.
Malfunctioning Throttle Position Sensor (TPS)
Your car’s engine control unit or ECU depends on a number of sensors to take off the vehicle. One crucial sensor is the throttle position sensor or TPS, which monitors the position of the throttle.
The ECU relies on the TPS data to determine how much air is entering the engine through the throttle. A malfunctioning TPS provides inaccurate information, so the ECU may not inject the right amount of fuel.
Hence, the imbalance in the air-fuel mixture ratio causes the car to hesitate during takeoff.
How to Fix?
If you’re lucky, resetting the TPS will solve the issue. All you need to do is disconnect your car battery for about 5 minutes. After that, reconnect the battery and turn on the ignition. Push your car’s gas pedal to drain the power.
It will reset the TPS and probably fix the hesitation issue. Otherwise, you need to remove the old TPS and install a new one. The sensor itself can cost $100 at most. The labor cost is around $50 at most.
Mass Air Flow (MAF) Sensor Issue
To power up your car engine during takeoff, the air-fuel mixture needs to be precise. The ECU uses the mass airflow sensor’s (MAF) data to calculate the exact amount of fuel that goes into the car engine, depending on the specific volume of air.
A bad or malfunctioning MAF sensor gives inaccurate data to the ECU, leading to an improper amount of air and fuel, which causes car hesitation. Erratic idling, dashboard warning light, black exhaust, etc., are some common signs of a faulty MAF sensor.
How to Fix?
Dirt or wear can cause the MAF sensor to malfunction. So, you need to clean or replace it depending on its condition. Below is the process:
- Disconnect your car battery and open the airbox of your car. Locate the MAF sensor and carefully remove it with a flathead screwdriver.
- If the sensor is dirty, you can use rubbing alcohol to clean it. For better results, purchase a mass air flow sensor cleaner and apply it as per the manufacturer’s instructions.
- For worn-out MAF sensors, you need to install a new one of the same configuration. The replacement may cost you a maximum of $350, including labor costs.
Bad Manifold Absolute Pressure (MAP) Sensor
As your car starts, the manifold absolute pressure (MAP) sensor measures the air pressure of the intake manifold. The data is later processed by the ECU, which decides how much air should be mixed with fuel.
A bad MAP sensor is responsible for providing inaccurate pressure readings. Hence, the car engine hesitates while accelerating. Apart from that, you’ll notice other symptoms such as overheating, a strong smell of fuel, slow acceleration, and jerking.
How to Fix?
In this case, you need to replace the bad MAP sensor with a new one. It’s best to get help from a professional. The price of the MAP sensor ranges between $20 to $150, based on the models and manufacturers. The labor cost can be around $20 to $40.
Faulty Oxygen Sensor
As the name implies, the oxygen sensor monitors the amount of unburned oxygen found in the exhaust gas. It allows the ECU to measure whether the fuel mixture is too rich or lean.
Faulty oxygen sensors fail to provide accurate data, so the car engine can’t make the necessary changes in the improper fuel ratio. Therefore, the vehicle starts to lag and deliver poor performance while taking off.
When the oxygen sensor malfunctions, it can trigger the dashboard warning light and a DTC. You can use a scan tool to be sure that you’ve got a malfunctioning oxygen sensor.
How to Fix?
To fix this issue, you need to clean or replace the oxygen sensor. However, the process is complicated, and you’ll need special tools like an OBD-II scanner to locate the faulty sensor. So, we recommend you visit a qualified mechanic to replace the oxygen sensors in your car.
It will cost you $150 to $500 on average, including the labor cost and price of the new parts.
FAQs
Want to learn more about why your car is hesitating upon acceleration? Check out the common queries car owners have regarding this issue.
Q. Can bad spark plugs cause engine hesitation?
Yes, bad spark plugs can cause engine hesitation. They play a crucial role in igniting the air-fuel mixture in the engine’s cylinders. Bad spark plugs fail to generate a strong enough spark, leading to incomplete combustion and engine hesitation.
Q. How do you diagnose engine hesitation?
To diagnose engine hesitation, first check if there’s any warning light on your dashboard. You can also inspect the ignition and fuel system for worn-out or malfunctioning components.
Finally, use a diagnostic scan tool to retrieve Diagnostic Trouble Codes or DTCs that provide specific information about the problematic components.
Q. What are the signs of engine hesitation?
Apart from hesitation, lag, and sputtering, other signs of engine hesitation include slow acceleration, jerking or stumbling, and rough idling. Your car engine might also misfire, produce unusual exhaust smoke, consume more fuel, and deliver overall poor performance.
Parting Thoughts
When your car hesitates on takeoff, it marks issues with your vehicle’s ignition system, air-fuel mixture, and fuel system. All the components of the ignition play crucial roles in starting the engine. Similarly, the fuel system controls the combustion which gives the car sufficient power to take off.
Therefore, when the ignition and fuel components (especially the sensors) go bad, your car fails to generate enough power to take. If your car is hesitating on takeoff, follow our given solutions to easily get rid of this issue.