Check Engine Light Flashing When Accelerating

It’s quite concerning to see the check engine light flashing when accelerating as it can make it difficult to control the car’s speed. A car’s CEL can flash while accelerating due to a cylinder’s misfire, damaged exhaust system, bad throttle body sensor, and ignition problem.

Since CEL’s flashing while accelerating is a serious issue, you shouldn’t continue driving the vehicle. Instead, diagnose the car using a scanner and solve the underlying issue before it damages the catalytic converter.

Causes of Check Engine Light Flashing when Accelerating

Misfire in the cylinders is the most obvious reason for causing the check engine light to flash when accelerating. The misfire can cause due to plenty of reasons including putting the wrong fuel in the fuel tank, wear out ignition coil, and damaged ECU.

It affects the emission control system, fuel efficiency, and the car’s overall performance. Scan the system by an expert mechanic and you’ll have error codes P0301, 302, and 303. Below are some common causes of CEL flashing when accelerating:

1. Damaged Exhaust System

Check engine light can flash continuously when accelerating due to a faulty exhaust system which results in an engine misfire. It can happen if one or more cylinders don’t get enough sparks from the ignition system or air doesn’t pass from the intake system to the cylinders. A damaged fuel injector can also cause this issue.

Damaged Exhaust System

2. Damaged Catalytic Converter

If you ignore the engine misfire, it can turn into a severe issue and damage the catalytic converters. If the check engine light flashes for a moment and then stops when you accelerate moderately hard, it’s an obvious sign of a bad catalytic converter.

Damaged Catalytic Converter

3. Damaged Throttle Body Sensor

If the engine starts stuttering and the check engine light blinks on and off when you accelerate, possibly the throttle body sensor gets damaged. If so, neglecting the issue can activate the limp mode and drive homes and make the car inefficient to drive. If the throttle body sensor is responsible, you may have to clean or replace it to restore its functionality.

Damaged Throttle Body Sensor

4. Ignition Problem

Various ignition system problems like bad wires and damaged spark plugs can cause CEL to flash when accelerating. It can also disturb the engine to maintain proper air and fuel mixture and activate the check engine light. it can end up causing increased emissions and poor engine performance.

5. Damaged Fuel Delivery System

The fuel delivery system supplies the tank’s fuel to the engine and maintains proper delivery at a certain pressure. However, it can malfunction due to fuel pump failure, damaged fuel injectors, blocked fuel filters, and vapor leaks.

It can drop the fuel level rapidly and cause the CEL flashing when accelerating. Though it brings minor consequences compared to other potential reasons, it requires deep diagnosing to fix this problem.

6. The Bad ECU

The camshaft position sensor monitors the car’s camshaft position and speed. it then delivers the information to the ECU which controls the fuel’s amount that enters into the combustion chamber and controls the fuel ignition’s timing.

The Bad ECU

When you accelerate, the car must adjust the ignition timing and fuel intake to a high degree. But if the camshaft sensor gets damaged, it can deliver wrong information to the ECU and disturb the ignition timing. Hence the check engine light may start flashing when you accelerate.

Risk of Driving with Check Engine Light Flashing when Accelerating

If the check engine light flashes red, you should stop driving the car immediately as it indicates that the damage is already done. However, you can drive the car to the mechanic if the light flashes orange. It sometimes indicates less serious problems like low fluid levels.

Engine misfire is the most common reason for checking engine light flashing. It can happen due to a failing spark plug coil that can overheat the catalytic converter. It can then melt the inside of the converter and plug the exhaust system and affect the combustion chamber.

While changing four spark plug coils can cost $160, replacing the catalytic converter and oxygen sensor can cost around $900. So you shouldn’t drive with the check engine light flashing until you determine what you are ignoring.

In terms of safety, it’s dangerous to drive with an engine misfiring. It might not let you get out in front of traffic and can cause an accident. Depending on the reason for CEL’s flashing, your car stops running immediately and blocks the traffic. You may also need to tow your car.

What to do If Check Engine Light Flashes When Accelerating?

CEL’s flashing when accelerating mostly indicates a serious problem engine of the engine and ignoring the issue can bring severe consequences. So if your car’s CEL flashes when accelerating, stop driving the vehicle at least at high speed.

What to do If Check Engine Light Flashes When Accelerating

Slow down the car and safely drive to the nearest auto repair shop. If you are more concerned, tow the vehicle to the service center or home garage. You can also call for emergency help. But keep driving with CEL flashes can increase the repair cost from hundreds to thousands.

However, the repair cost may vary depending on the exact problem. For example, replacing the full set of spark plugs can cost around $100 to $150 while changing the fuel injector can cost up to $500.


Why is the Check engine light flashing and the car shaking?

If your car’s CEL flashes and the car shakes at a time, it can be the result of a bad emission system and an engine’s misfire. The bad spark plug or damaged ignition coil can also dump unburnt fuel into the exhaust and make the car shake.

Why check the engine light flashing and the car won’t accelerate?

A faulty ignition coil can cause a check engine light to flash and prevent the vehicle from accelerating. If you continue to drive the car in this condition, it can damage the catalytic converter which is very expensive to replace.

Can a bad throttle sensor cause a misfire and check engine light flashing?

Yes, a faulty throttle sensor can cause an engine to misfire as it can disturb the ignition timing and stop it from working. The car’s stalling or rough idling is a clear sign of a bad throttle sensor. It can also force TPS to deliver incorrect data even when the accelerator isn’t pressed.

Final Words

If your car’s check engine light flashes when accelerating, park the car in a safe place instead of keep driving. If you have a scanner like OBDII, use it to determine the error code that may cause the issue.

If you don’t have the tool, consult with an expert mechanic. In either case, you should bring the car to the nearest service center. CEL flashing when accelerating isn’t a minor issue that you can ignore for a long. 

My name is Tom Vanderbilt. I am an automotive expert and renowned for my profound knowledge of automobiles. I have made significant contributions to the industry through my experience and expertise. I have a natural curiosity and fascination for cars. My journey is to explore the intricate dynamics between people, their vehicles, and the ever-evolving transportation landscape.

1 thought on “Check Engine Light Flashing When Accelerating”

  1. I never realized how serious it is to have the check engine light on while accelerating. I’ll make sure to keep an eye on it from now on and address any issues promptly. It’s great to know that there are safe distances to drive with the warning light on. I’m still worried about what could happen if it’s left unchecked for too long. Can you please share more about the potential consequences of ignoring the check engine light?


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