Ford F150 Check Engine Light Flashing Then Stops

So you took out your Ford f150 for a drive and suddenly noticed that the check engine light is flashing and then it stops. Is that a problem?

Yes, it is. It means that your engine is misfiring. Reasons can be anything from a malfunctioning spark plug to a damaged catalytic converter. You need to get it quickly because any negligence can be harmful to you. There is a risk of accidents involved. 

Now, what do you do then? Well, If you want to know more about these reasons and how to solve them, then read this article. 

Should You Be Worried?

Yes, check engine light flashing and then stopping means that your engine is misfiring. Do not drive. Get it towed and fix it as soon as possible. 

Why Does It Flash Then Stop?

ford f150 check engine light flashing
Source: f150forum

Have a quick look at the table to know the reasons and solutions for this light flashing.

Worn Out Spark Plug or Ignition CoilReplace Spark Plug or Ignition Coil
Faulty O2 SensorReplace O2 sensor
Bad Mass Airflow SensorReplace Mass Airflow Sensor
Damaged Catalytic ConverterReplace Catalytic Converter
Clogged EGR SystemUnclog EGR System

So, how to stop the check engine light from flashing? Diagnose the code using a scanner. 

Now, based on the result, either replace the spark plug or the catalytic converter or something else based on what the code shows. 

Reason 1: Worn out Spark Plug or Ignition Coil

Ford f150 check engine light flashing when accelerating can happen because of a worn out spark plug or ignition coil. The task of a spark plug is to make sure that the spark happens properly to ignite the air-fuel mixture. 

However, if the spark plug itself is worn out then it won’t provide the spark or the spark will happen at inappropriate cycles. It will lead to problems like engine misfiring, the engine starts and dies immediately

Since the check engine light flashes and then stopping is because of engine misfiring, a worn-out spark plug or ignition coil is one of the key reasons for this problem.

Following are some of the symptoms of a bad spark plug:

  • Hard starting
  • Rough Idling
  • Poor acceleration

Code expected – p0301


To solve this problem you need to replace the spark plug or ignition coil. Here is how you can replace the spark plug to solve the 2016 Ford f150 blinking check engine light 

Tools Required:

  • Spark plug wires
  • Anti-seize lubricant 
  • Dielectric grease
  • ⅜  drive ratchet
  • ⅝ spark plug socket
  • 8mm socket
  • 10mm socket
  • Torque wrench
  • Screwdriver

Step 01: Remove the oil cap and the engine cover piece. Once the engine cover piece is removed, replace the oil cap.

Step 02: Remove the foam insulation and blow around the spark plug compartment to avoid getting any dirt into the spark plug.

Step 03: Now go to cylinder 01 and unplug the coil and remove it. Make sure to wiggle out the ignition coil rather than pulling it out. 

Step 04: Once the ignition coil is removed, you will find the spark plug. 

Step 05: Remove the spark plug using the ⅝ spark plug socket.

Step 06: Now replace the ignition coil boot and put dielectric grease around it.

Step 07: Grab the new spark plug that you want to replace the old one with. Make sure that there is no crack in it.

Step 08: Put the new spark plug in the thread and connect it properly.

Step 09: Now connect back the ignition coil.

Step 10: Repeat the same for all the remaining cylinders in the engine. 

Step 11: Connect back the foam insulation and the engine cover.

Step 12: Start the engine and check if the light is still on.

Although if you are not into DIY work, get it replaced by a professional. It should cost you $300. However, the price varies by state. 

Reason 2: Damaged Catalytic Converter

Catalytic converter helps to reduce emissions in your car. But if it is damaged then it can’t filter out the pollutants. Whenever that happens your ford check engine light flashes and then stops. 

Following are some of the symptoms of a damaged catalytic converter

  • Random Engine Misfiring
  • Decreased Acceleration
  • Rattling Noise
  • Sulfur Smell from the exhaust

Code expected: p0430


To solve this problem you have to replace the catalytic converter

Following is the process of replacing the catalytic converter on a Ford f150

Tools Required:

  • 21mm socket
  • 18mm socket
  • 13mm socket
  • 10mm socket
  • Swivel socket
  • Universal swivel joint
  • 15mm open end wrench
  • 22m wrench
  • ⅜ ratchet

Step 01: Lift the truck up properly using a jack stand.

Step 02: Find the catalytic converter location and soak the threads using WD-40 spray.

Step 03: Remove the shield surrounding the converter using the 13mm socket.

Step 04: Remove the bolt holding the passenger side heat shield. 

Step 05: Next you have to use the 21mm socket to remove the nuts holding the transmission mount to the transmission cross member.

Step 06: Lift the transmission up using a floor jack or bottle jack.

Step 07: Next remove the four bolts holding the transmission cross member using the 18mm socket and 15mm open-end wrench.

Step 08: Remove the mounts for the exhaust using a 15mm socket.

Step 09: Remove the connectors of the O2 sensors and then all the nuts connected to the downpipe to the turbocharger.

Step 10: Using the 13mm socket remove the bolts holding the downpipe assembly to the exhaust.

Step 11: Finally, with all the bolts removed, you can take off the downpipe assembly including the catalytic converter off the truck.

Step 12: Now, remove the O2 sensors and install them into the new downpipe assembly including the new catalytic converter.

Step 13: Put the downpipe assembly back into the truck and then insert back the transmission mount.

Step 14: Fix everything back in reverse order and make sure everything is fitted properly.

Step 15: Now lower down the truck and start the engine to check if the engine light is still blinking.

However, due to the complexity of the process we recommend consulting a professional for this task. It should cost you $1560-$1585

Reason 3: Faulty O2 Sensor

O2 sensor keeps track of the air inside the combustion chamber and based on that it sends a signal to the PCM. However, if the sensor itself is damaged then it won’t be able to send correct information.

This leads to problems like engine misfiring

Code expected – p0130 or p0150


You need to replace the faulty O2 Sensor to fix this issue. Follow the steps for replacing the catalytic converter discussed here

You will find that the O2 sensor is in the same compartment. Just replace it with a new one. A good O2 sensor should be around $100

Reason 4: Bad Mass Airflow Sensor

Mass airflow sensor keeps track of the airflow to the engine intake. A malfunctioning sensor means that the air-fuel ratio will not be properly maintained and therefore the engine misfiring or has a problem with the RPM ratio

Following are some of the symptoms of a bad mass airflow sensor:

  • Engine stalling or hard to start
  • Engine Jerking
  • Way too much rich or lean mixture

Codes expected – p0100, p0101, p0102, p0103, p0104. 


Replace the mass airflow sensor to solve this problem. Following is the process of replacing the mass airflow sensor on a 4.6L engine of a 2002 Ford f150.

Step 01: Pop the hood and disconnect the battery.

Step 02: Now find the mass air flow sensor and disconnect it from the wiring harness.

Step 03: Release the air cleaner clamp and separate the inept and outlet sides.

Step 04: Grab the outlet side and remove the wiring and the slide inside.

Step 05: You will finally get the mass airflow sensor and now you have to disconnect the electrical connections.

Step 06: Separate the sensor from the plate and then check for any debris.

Step 07: Install the new mass airflow sensor on the plate.

Step 08: Now install it back to the plate and connect back all the electrical connections. Wait for a click sound when it is connected back.

Step 09: Reconnect everything back in the reverse order.

Step 10: Start the engine and check.

Again, you can find a good mass airflow sensor within $100

Reason 5: Clogged EGR System

The EGR system helps to reduce the nitrous oxide emission from your car. Its task is to recirculate the exhaust gas back to the intake system. However, due to the continuous process, EGR valves become prone to clogging and gradual damage.

So, you have to unclog or replace it whenever the EGR system is not working properly.

Following are some of the symptoms of a clogged EGR system 

  • Rough Idling
  • Increased engine vibration
  • Increased fuel consumption

Code expected: p0401


Following are the steps of unclogging the EGR system on a 1998 Ford f150

Tools Required:

  • Wire brush
  • Acid resistant gloves

Step 01: Pop the hood and find the EGR Valve.

Step 02: Disconnect the hoses from the EGR valve and bring out the valve.

Step 03: Bring out the wire brush and clean it. Spray over the carbon deposit with EGR valve cleaner.

Step 04: After you’re done clearing, put the valve back and connect it properly. 

However, if your EGR valve is severely clogged or damaged, you can replace it. 

At this point, it should be very clear to you what causes the check engine light problem in your Ford f150. Follow the points here to solve it easily. 

Frequently Asked Questions (FAQs):

How Many Miles Can I Drive With Ford F150 Check Engine Light Flashing?

None. You should not drive if your check engine light is flashing. Please stop the car and get it towed to the nearest servicing station. If you keep driving your Ford f150, you are risking the internal engine components especially the catalytic converter. 

How Do I Know Which Cylinder Is Misfiring?

Grab your scan tool and diagnose the code. If the code shows p0301 that means cylinder 01 is misfiring but if it shows p0302 it means it is cylinder 02 that is misfiring. 

Does Check Engine Light Flashing Mean the ECU Is Damaged?

No, check engine light flashing means that your engine is misfiring. In fact, it is the ECU that receives this data and sends this information to the Check Engine Light. Based on the information, it flashes. 


So, now it must be clear what happens when Ford F150 checks engine light flashes then stops. It is a risky situation and you need to take a step as soon as possible. 

Hopefully, through this article, you have a clear guideline on how to approach this issue.

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