Is Your Car Not Accelerating? Here’s How to Fix it!

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Car Accelerating

When your car cannot accelerate when you push down the gas pedal, it can be confusing and frustrating. In times like these, keep in mind the most common reasons for these and how to resolve them before things worsen.

What Does Car Acceleration Mean?

Slow acceleration is a fire-breathing monster of motion variables contrasted to displacement and velocity. It can be aggressive; some people are frightened of it, and, if huge enough, it forces you to pay attention.

Acceleration refers to any method in which velocity changes. Since velocity is both a speed and a direction, you can only accelerate in one of two ways: modify your rate or change your order—or both.

If you're not changing your direction or speed, acceleration would not be possible no matter how swiftly you're traveling. For example, a jet flying at 800 miles per hour along a straight line has zero acceleration, even though it moves very quickly because velocity is constant. When the plane slows down, it will accelerate when it is about to land and comes to a sudden stop.

You may also consider it this way—in an automobile, the driver can accelerate by pressing the gas pedal or while braking, which results in a change in speed. Re-ordering the car by shifting into a higher gear to go faster allows the engine to do more work. However, it may not be an option if you're already in first gear.

Even if it does not speed up or decelerate, a moving object's change in the order of motion still results in acceleration. Its velocity can sometimes change by the same amount every second, thus producing continuous acceleration.

So why does your car accelerate when you've ordered it to slow down? 

It's pretty simple—the change in velocity determines acceleration. This means any velocity adjustment, like modifying the direction, increasing or decreasing speed, is still considered acceleration.

To sum it up—Acceleration is caused by any changes in an object's velocity:

  • Increasing speed (what most people mean by acceleration).
  • Decreasing rate (also known as deceleration or retardation).
  • Changing direction (called centripetal acceleration).

Causes of Car Acceleration Problems

1. Air Delivery Problems

The air filter should be checked for any dirt, debris, and other contaminants if the car isn't accelerating as it should. A blocked air filter prevents an engine from vital air that can cause the air-fuel mixture to affect acceleration.

2. Fuel Delivery Problems 

A blocked or unclean fuel system can deplete an engine's fuel supply, resulting in limited engine power. A contaminated fuel filter can cause this, a blocked fuel tank strainer, clogged or faulty fuel injectors, or a damaged fuel pump. Changing the fuel filter on most cars can be done by yourself.

3. Ignition Delivery Problems 

Ignition systems are created to generate a powerful spark that results in the firing up of the air/fuel mixture. A combination of messy or old spark plugs and bad ignition wires or coils stops fuel in the combustion chamber from completely burning, thus resulting in a loss of power. 

The replacing of spark plugs and wires may be done by yourself, but coil diagnosis and replacements should be best left with your mechanic.

4. Emission Control Sensors 

Any malfunctioning emission control equipment can illuminate the Check Engine light. If the ECM detects a significant issue, it may switch to "limp home mode," reducing engine power to safeguard the transmission.

5. Mechanical Issues

A car that does not accelerate well when you press the gas pedal must be inspected and fixed by a professional as soon as possible. Continuing to drive with these problems might lead to more significant and costly repairs. 

Many of the fixes proposed here are low-cost, straightforward, and can be done by yourself at home. If these don't fix your speed difficulties, take your car to a reputable, expert mechanic to figure out what's wrong.

Symptoms of Problems in Car Acceleration 

The most prevalent symptoms are a loss in vehicle performance, a sluggish acceleration, and a drop in power.

Other signs and symptoms may include:

  • erratic idle
  • a difficult-to-start automobile
  • reduction in fuel efficiency
  • a noticeable lag is felt and heard while pressing on the brake
  • delay on shifting into drive or reverse before pressing on the gas pedal
  • surging or jerking while driving

How to Determine Car Acceleration Problems?

Before we conclude why your car is not accelerating like usual, it will be helpful to know how your vehicle gains speed. The throttle pedal connects directly to your car's engine, regulating the amount of air entering the intake or the carburetor. 

With air being combined with the gas and fuel injectors or a carburetor being introduced with spark plugs, this results in combustion, which forces the engine's pistons down to turn the crankshaft. It turns the car's driveshaft to allow the vehicle to move forward.

Knowing how acceleration and velocity work, we can now discuss the possible fixes for your car acceleration problem. 

Step-by-Step Guide

  • The most common problem for your car not accelerating is a deflated tire. As a result, the best thing you can do is go to your local gas station and fill them up. After that, your car should be able to drive normally again. And don't forget to inflate them now and then. If they aren't inflated for a few months, they can lose air.
  • If inflating your tire does not solve the problem, check if your emergency brake is on. This usually happens to new drivers, but don't think you're exempted because it can happen to anyone at any time. So, check your emergency brake and turn it off if you notice the car slowing down.
  • If it's not your emergency brake that causes the problem, check your fuel tank. Bad fuel can ruin your car performance, so you should try other gas stations as some of them have additives added to their fuel that makes the engines work much better. Also, do not drive on reserve fuel and nearly empty tanks as it will cause poor engine performance. 

These are the simple fixes for a car that isn't accelerating. Let's now move on to a more complicated problem requiring more troubleshooting and car knowledge. However, we will simplify these issues to understand them better and resolve them. So, let's get started.

Sparkplug is one of the crucial parts of the car. If the sparkplug fails, it will cause your car to drive poorly, and it won't be easy to accelerate. A build-up of carbon could cause this if the fuel in the mixture is rich. In this case, it's best to replace the broken spark plug with a new one.

Replacing a sparkplug should be done by a professional. However, if you are knowledgeable in automobile repairs, you can also try it yourself. To get started:

Removing the Sparkplugs

  1.  Ensure to disconnect the negative battery terminal. 
  2. Check for any covers and remove if necessary.
  3. Clean the area around the spark plugs by using a vacuum to prevent dirt from falling into the spark plug or the engine.
  4. Remove the spark plug boots. It's important to keep the engine fires in order, so use a labeling method to mark which wires go to which plugs as you go.
  5. Remove the spark plugs and check for damage, build-up, or foreign materials.

Installing the Sarkplugs

  1. Before installing a new sparkplug, make sure to check if it comes with a preset gap. It ensures no leakage will occur on the sparkplug that can affect the engine performance.
  2. Thread the new plugs back into the engine using a plug starter or a socket extension. After that, cross-thread the plug or over-torque.
  3. Make sure to look up the torque specifications for your vehicle and tighten the spark plugs with a torque wrench.
  4. Reconnect the plug boots to their respective plug mates.
  5. Reconnect the battery, and you're done!

Vehicles in Modern Age

Vehicles are subsystems that serve specialized design roles. Thousands of parts have evolved from innovations in current technology or new technologies like electronic computers, high-strength polymers, and novel steel and nonferrous metal alloys, to name a few.

The sign of a car not accelerating properly usually happens on several high-mileage automobiles. Normally, the car owner cannot detect these symptoms while driving on an ordinary day. These problems become apparent while driving on a steep hill, and the driver immediately tries to shift quickly and accelerate.

The weight distribution between the front and rear wheels, the height of the center of gravity, and its position relative to the vehicle's aerodynamic center of pressure, suspension characteristics, and the choice of which wheels are used all have a role that may cause instability. 

Traditionally, the roofs of automobiles are supported by pillars on each side of the vehicle. Because convertible mechanics and glass regions are largely nonstructural, convertible cars with retractable fabric tops rely on the post at the side of the windshield for upper body strength. 

The amount of glass in the car's construction has been increased for better visibility and aesthetic reasons.

Car Acceleration Problems FAQ

1. What will the mechanic do to fix my car acceleration problem?

If you've checked and done fixes on your car and it still has problems, it may be time for you to send your vehicle to the shop. 

The mechanic will inspect your vehicle's fuel system for leaks and damaged parts. These include gasoline injectors, the fuel pump, a fuel filter, airflow sensors, and other critical components to the automobile's gradual acceleration. Test driving the car may be required to confirm the acceleration problems, so an appropriate diagnosis and fix are made.

2. How is Slow Acceleration serious?

A slow-moving car is risky to drive, especially at crossroads, inclined places, and on-ramps. The failure to remedy minor fuel system issues may result in more expensive repairs in the future. If your car is unable or is slow to accelerate should be evaluated and fixed as soon as possible.

3. How do deflated tires affect my car's acceleration?

Deflated tires are the most common problem of cars that cannot accelerate properly. Whenever you leave the house, always take time to check your vehicle's tire condition to avoid any problems on the road. Doing so will grant you a peaceful and safe ride.

4. How does the brake system affect my overall car performance?

An issue with your brake system can cause your car to have poor acceleration and be undrivable. Problems like these should be dealt with as soon as possible to avoid more damage to your automobile. To prevent this, You should check brake system calipers, brake disks, and brake oils monthly.

5. Can engine problems cause poor acceleration?

Engine issues are a significant problem, leading to poor acceleration in automobiles. The common cause is an oil leak that results in loss compression and low horsepower ratings. You should always check and pay attention to the performance of the engine. 

If anything feels unusual, take your car to an auto service center so it will be appropriately diagnosed and checked by professional mechanics.


Car acceleration issues will not go away if you ignore these. As we've mentioned here, there are several causes behind it. The sooner you send your car to its service center, the sooner all the problems will be corrected. Regular maintenance will help in avoiding this in the future. We hope that this guide helps you determine your car's acceleration issues.