Check Engine Flashing but Car Not Accelerating

Driving is therapeutic for me; it’s one of the ways I let out the heat, but when troubles like a flashing check engine light rears its head, I begin to question my choice of relaxation.

It is even more troubling if the car won’t accelerate. This article will answer the question: why is the check engine flashing but the car not accelerating?

This occurs when one or more cylinders misfire due to bad fuel injectors or sensor failure. When the onboard computer detects such a problem, it triggers limp mode to prevent further damage.

When this happens, the car will not accelerate as it usually would, and simultaneously, the flashing check engine light alerts you to the underlying issue.

In this blog post, I’ll discuss why the check engine light is on, why your car won’t accelerate, and how to diagnose and fix the issue. 

Check Engine Flashing but Car Not Accelerating

Causes of The Check Engine Light And Car Not Accelerating?

Here are common causes of the check engine light flashing and a car’s failure to accelerate:

1. Engine Misfire

A severe engine misfire, often caused by faulty spark plugs, ignition coils, or fuel injectors, disrupts the combustion process. This leads to reduced power output, resulting in poor acceleration.

2. Sensor Failures

Issues with the sensors, such as the mass airflow sensor or throttle position sensor, can provide incorrect data to the engine control unit (ECU).

This can cause the ECU to adjust the air-fuel mixture incorrectly, leading to a misfire and reduced acceleration.

3. Fuel Delivery Issues

Problems with the fuel system, including a clogged fuel filter or a failing fuel pump, can hinder the proper delivery of fuel to the engine. This leads to inadequate combustion and poor acceleration.

4. Transmission Problems

Issues within the transmission, such as slipping clutches or a malfunctioning torque converter, can result in power loss and hinder acceleration.

5. Exhaust System Concerns

A restricted or damaged exhaust system, including a clogged catalytic converter, can impede exhaust gas flow, causing the engine to perform poorly and limiting acceleration.

6. Ignored Check Engine Light

When the initial warning of a solid check engine light is disregarded, it can escalate problems within the engine or emission control system.

Subsequent issues, if not addressed promptly, can result in the car entering a protective “limp mode,” severely limiting acceleration.

7. Bad Fuel Injector

A malfunctioning fuel injector can disrupt the precise delivery of fuel into the engine’s cylinders, causing an uneven air-fuel mixture.

This imbalance can lead to misfires and hinder acceleration. If one or more fuel injectors fail or become clogged, the problem can further exacerbate, reducing engine performance and responsiveness.

8. A Leaking Head Gasket

The head gasket seals the cylinder head to the engine block, ensuring proper compression and preventing coolant and oil from mixing.

When the head gasket leaks, it can allow coolant to enter the combustion chamber, causing misfires, reduced engine power, and poor acceleration. 

Fixing Check Engine Light Flashing, No Acceleration

Fixing a check engine light accompanied by poor acceleration requires practical steps for diagnosis and resolution. Here’s a practical guide to address these issues:

  • If the check engine light flashes, immediately reduce your speed and pull over to a safe location. Turn off the engine to prevent further damage or risks.
  • Use an OBD-II diagnostic scanner, readily available at auto parts stores, to retrieve error codes from the vehicle’s computer, especially in cases when the check engine light is flashing with no code. These codes provide a starting point for identifying the problem.
  • Refer to the scanner’s manual or online resources to interpret the error codes. They’ll help pinpoint potential issues, such as sensor malfunctions or misfires.
  • While parked safely, visually inspect the engine bay for loose or disconnected wires, hoses, or damaged components. Address any visible issues.
  • Ensure that the fuel cap is securely tightened. A loose or missing fuel cap can trigger a check engine light. Tighten it if necessary.
  • In some cases, a temporary glitch can trigger the check engine light. Turn off the engine, wait a minute, and then restart the vehicle to see if the light remains illuminated.
  • Based on the error codes and initial diagnosis, inspect specific components. This may include spark plugs, ignition coils, oxygen sensors, and the air intake system.
  • Inspect the air filter for clogs or excessive dirt. A dirty air filter can affect engine performance.
  • Examine the fuel system for clogs or fuel delivery issues. Ensure the fuel filter is clean, and the fuel pump is functioning correctly.
  • If you suspect transmission issues, consult a professional. Transmission problems often require specialized knowledge and tools.
  • After making any necessary adjustments or repairs, take the vehicle for a test drive to confirm whether the acceleration problem persists and if the check engine light remains off.
  • If you’ve resolved the issue, use the diagnostic scanner to clear the error codes.
  • To prevent future issues, adhere to a regular maintenance schedule, including oil changes, air filter replacements, and spark plug maintenance, as recommended by your vehicle’s manufacturer.

What is the Cost Estimate to Fix Poor Acceleration?

The average cost of repair is around $100 to $500. However, the cost to fix can vary significantly depending on the specific underlying issues, the make and model of the vehicle, and labor rates in your area.


Why is my car not accelerating and misfiring? 

When there is an issue igniting the air-fuel mixture correctly in one or more cylinders, it leads to misfires and reduced power output, causing the acceleration problem. Which then triggers a flashing check engine light.

Why is my engine light flashing and loss of power? 

This occurs when one or more cylinders in the engine fail to ignite the air-fuel mixture properly, leading to reduced power output and poor acceleration. While the flashing engine light indicates the severity of the problem


A check engine light accompanied by poor acceleration indicates cylinders misfiring. Issues like bad fuel injectors, sensor issues, etc., could cause this. 

However, timely diagnosis and resolution of these issues are essential not only for the vehicle’s performance but also for safety. 

Therefore, follow the practical steps outlined in this guide, from safety precautions and diagnostics to addressing specific components, and seek professional assistance if you can’t effectively tackle the problem. 

Also, regular maintenance and prompt attention to warning signs are key to ensuring the continued reliability and functionality of your vehicle.