Ford F150 multiple cylinder misfire can happen for different reasons ranging from the engine spark plug malfunctioning to fuel filter getting clogged. Mostly it is related to the spark plug and parts directly related to it such as the ignition coil. However, you need to watch out for any problem in the fuel system. If there is a problem in the fuel trim number or any leakage inside the combustion chamber then you will get cylinder misfiring on your f150.
Keeping all this in mind you need to diagnose properly and verify the source of Ford F150 multiple cylinder misfire. To get into the details of the reasons and its diagnosis process, let’s get started.
Can I Drive with Multiple Cylinder Misfire on Ford F150?
No, you can not drive with multiple cylinder misfires on a Ford F150. Engine Misfiring is a serious problem and it means that the combustion process is not happening properly. If you continuously keep driving despite misfiring, you are putting your engine at a risk of massive damage. Perhaps the catalytic converter and fuel injector can get damaged. Overall, if the cylinder is misfiring, stop everything and get your truck towed.
5 Major Reasons for Multiple Cylinder Misfire on Ford F150
Now we need to know the reasons that cause multiple cylinder misfires on Ford F150. Let’s go through each of the reasons, its diagnosis and solution.
| Reasons | Symptoms | Solution |
| Faulty Spark Plug | 1. Engine Starting Problem 2. Reduced acceleration | Replace Spark Plug |
| Damaged Ignition Coil | 1. Engine Starting Problem 2. Rough Idling 3. Bad Fuel Economy | Replace Ignition Coil |
| Clogged Fuel Filter | 1. Engine Stalling 2. Loud Noises from fuel pump | Replace Fuel Filter |
| Faulty Fuel Injector | Engine Stalling Rough Idling | Replace Fuel Injector |
| Defective Camshaft Sensor | 1. Engine Starting Problem 2. Engine Stalling | Replace Camshaft Sensor |
Faulty Spark Plug
Spark Plugs help to generate the required spark to ignite the air-fuel mixture in the combustion chamber. Located above the cylinder head it is an integral part of the combustion cycle and that’s why it regularly gets exposed to the inner environment of the combustion process.
Because of this, there are many ways a spark plug can go bad. Firstly, there is the problem with your air fuel mixture in the engine cylinder being too rich (revving too much fuel). Too much fuel in the combustion chamber will hamper the spark plug by depositing a layer of carbon on the spark plug electrode. So, if the mixture is running rich, then you need to fix the source of that before you replace the spark plug.
If the O2 sensor is faulty, or if there is a leaking injector or the fuel pressure regulator is not performing properly then the air-fuel mixture will run rich. Fix these issues first and then replace the spark plug. Otherwise, you will keep replacing your spark plug while your engine will run rich.
Now, if there is any oil or coolant leak in the combustion chamber then again the spark plug working will be affected. So make sure to check for leakage inside the combustion chamber.
One way to verify a leak is if the spark plug has the smell of oil or if there is a layer of greasy looking dirt over the spark plug. This is an indication of leak inside the combustion chamber.
Beyond both leakage and rich mixture, a spark plug will also get damaged through overheating. Overheating can happen through a multitude of problems like advanced ignition timing, lean air-fuel mixture, low fuel octane rating or insufficient engine coolant. All of these will lead to eventual damage of the spark plug.
Finally, your spark plug can get damaged through prolonged use. You need to replace the spark every 50,000 to 90,000 miles. Otherwise it becomes prone to wear out and get damaged.
Symptoms
Following are some of the symptoms of a faulty spark plug
- Difficulty in Engine Starting
- Reduced Gas Mileage
- Lack of Acceleration
- Rough Idling
Normally, you find out the code P0300 and know that there are multiple cylinder misfiring problems. However, once you verify that, a common suspicion is perhaps the spark plug is faulty. So, diagnosing the problem is necessary.
Unfortunately, there is no other way to diagnose it than checking the spark plug itself. Remove the spark plug wire first. Next you have to remove the spark plug using a socket. Once you are done removing the spark plug, check for any dirt or debris. Look at the condition of the spark plug. The table below shows the condition of the spark plug and what you can deduce from it.
| Condition of the Spark Plug | Reason |
 | Oil Leakage |
 | Engine Overheating |
 | Spark Plug Wearing Out |
 | Rich Air-Fuel Mixture |
 | Fuel Additives |
Always watch out for the following visual symptoms. If you find out that the spark plug is in any of these conditions in the table then the spark plug is already damaged and you need to replace it. Sometimes, you need to go through multiple solutions.
Let’s assume, your spark plug looks rusty then there are issues with the fuel additive. Normally, these are chemical compounds added to the fuel to enhance the performance. If the fuel or the additive in it is of low quality then the spark plug will also be damaged. In that case, you need to replace both the spark plug and the fuel.
Solution: Replace Spark Plug
Following are the steps of replacing the spark plug on 2014 Ford f150 with a 3.5L EcoBoost engine.
Tools Required:
- 8mm socket
- ⅝ inch socket
Step 1: Pull out the engine cover and then use compressed air to clean around the surrounding of the spark plug area.
Step 2: Go to cylinder number one and unplug the coil from it.
Step 3: Next grab the 8mm socket and remove the bolt to gain access to the ignition coil. Wiggle out the ignition coil. Make sure to do this carefully and not shred the boot.
Step 4: Now use a ⅝ spark plug socket to fully seat it on the spark plug nut. Rotate the spark plug counterclockwise and then remove it.
Step 5: Grab the new spark plug and then install it. Replace the old coil boot with the new one and add some dielectric grease around the boot.
Step 6: Finally connect back the ignition coil and the bolt. Repeat this process for the other affected spark plug.
Therefore, the process of replacing the spark plug is quite simple. If you want to have a visual guide then follow this How to Replace Spark Plugs Ford F-150 3.5L EcoBoost V6 – EASY! video.
The Damaged Ignition Coil
Ignition coil is directly related to the spark plug. It helps to transform the low voltage to a high enough voltage to power the spark plug to ignite. Now the ignition coils can go bad for a lot of reasons from an oil leak to spark plug wells to problems in the ignition coil connector. Beyond that, it is also prone to wearing out after every 1,00,000 miles.
All of this means that the ignition coil will not work properly and lead to multiple cylinder misfiring.
Following are some of the symptoms of a damaged ignition coil
- Reduced acceleration
- Rough idling
- Bad fuel economy
- Difficulty in starting
Now that you know the symptoms of a malfunctioning ignition coil. Let’s check the diagnosis process. First check the wiring surrounding the ignition coil. Look at the spark plug wires and the coil on plug ignition coil wires.
If it is loosely connected then connect it back properly. However, if the wiring is damaged then the ignition coil is not working properly. But if the wiring is fine then the ignition coil is physically damaged and requires replacing.
Solution: Replace Ignition Coil
The process of replacing the ignition coil has already been covered with spark plug replacement process. Make sure to go through that process, remove the ignition coil and install back a new one.
You can check this video How to Replace Spark Plugs Ford F-150 3.5L EcoBoost V6 – EASY! for a visual demonstration of the process.
Clogged Fuel Filter
Through prolonged use if the fuel filter gets clogged then it causes problems in the fuel flow. This can lead to problems like low fluid pressure and an overall lean air-fuel mixture. The direct consequence of low fuel pressure is engine misfiring.
Following are some of the symptoms of a clogged fuel filter
- Difficulty in starting
- Rough idling
- Engine stalling
- Loud noises from the fuel pump
Solution: Replace Fuel Filter
The solution is to just replace the fuel filter. This is quite simple.
Step 1: Begin by gathering the necessary tools, including a fuel line disconnect tool, to change the fuel filter.
Step 2: Position yourself underneath the middle of the vehicle to locate the fuel filter, which can be seen by looking up.
Step 3: Identify the clip on the front side of the fuel filter that needs to be removed. This clip retains the fuel line to the filter.
Step 4: Pop off the clip to fully detach it from the filter. It may be helpful to demonstrate this in the video.
Step 5: Use the fuel line disconnect tool to disconnect the fuel line from both sides of the filter. Insert the tool and pop the line off.
Step 6: Repeat the disconnection process for both sides of the fuel filter.
Step 7: Install the new filter, ensuring it is securely held in place by the retainers.
Step 8: Start the vehicle to check for proper installation and to ensure there are no leaks.
This How To Replace The Fuel Filter On A Ford F-150 is a good guide to help you with the process.
Faulty Fuel Injector
As the name suggests, a fuel injector helps to supply fuel to the combustion chamber. If the fuel injector is not working properly then there will be problems in the fuel flow. The result will be non-uniformity in the engine cycle during each stroke. So, that will lead to engine misfiring.
Solution: Replace Fuel Injector
A clogged or faulty fuel injector is a common problem on f150 diesel. But you will also find it on gasoline engines. The solution is simple, all you need to do is just replace the fuel injector. Following are the steps of replacing the fuel injector
Step 1: Begin by releasing the fuel pressure in the system. Locate the fuel rail on the passenger side of the engine, and remove the cap on the Schrader valve.
Step 2: Take necessary safety precautions by wearing gloves and safety glasses. Surround the valve with a paper towel or rag, and use a flat-head screwdriver to depress the valve.
Step 3: Once the fuel pressure is released, put the cap back on the Schrader valve to prevent fuel leakage.
Step 4: Remove the two ten-millimeter screws securing the fuel rail. Start with the rear screw using a 10mm socket on a quarter-drive ratchet.
Step 5: With the screws removed, gently pry between the injector and the fuel rail to lift the fuel rail off the injectors.
Step 6: Disconnect the injector connectors by squeezing the tabs on the top and pulling them off. Ensure that the injectors have O-rings intact on the top and bottom.
Step 7: Some injectors may remain stuck in the intake manifold. To remove them, unplug them with the clips on the top by squeezing the tabs and pulling them off.
Step 8: Inspect the old injector and compare it to the new one. Note any differences in design, but remember that they will fit and function the same way.
Step 9: Before installing the new injectors, lubricate the top seals with motor oil for easier insertion into the intake manifold and fuel rail.
Step 10: Install the new injectors one by one, sliding them into their respective holes in the intake manifold. Ensure they are properly seated. Then, reinstall the fuel rail by pushing it down over the injectors, starting from the rear. Use the two ten millimeter screws to secure the fuel rail.
Step 11: Finally, plug in the electrical connections for each injector by pushing them down until they latch.
Check for the location of the fuel injector it is normally around the intake manifold and replace it.
Defective Camshaft Sensor
Camshaft sensor helps the engine to determine the exact position of the crankshaft drive. If the camshaft sensor is damaged then it fails to send accurate data. The result is mismatched fuel delivery and improper ignition timing from which you can get engine misfiring.
Following are some of the common symptoms of a defective camshaft sensor
- Engine Stalling
- Difficulty in Starting
- Rough Idling
- Reduced Fuel Economy
If you find any of these problems then it is time to replace the camshaft sensor.
Solution: Replace Camshaft Sensor
Following are the steps of replacing the camshaft sensor on a 2004 F150 5.4 litre V8 engine.
Tools Required:
- Wrench
- 8 mm socket
- 10 mm socket
Step 1: Pop the hood and disconnect the negative terminal of the battery.
Step 2: Grab the 10 mm bolt and remove the air intake plumbing.
Step 3: Now remove the 8 mm bolt that holds the sensor into the cylinder head and then pull out the sensor from its socket.
Step 4: While removing the sensor, make sure that it has the O-ring attached to it.
Step 5: Locate the O-ring in the new sensor. Push the sensor through the hole and keep it all the way in.
Step 6: Connect the 8 mm bolt and then reconnect the sensor plug from the wiring harness.
Step 7: Finally, install back the air intake plumbing and torque the 10mm bolt to 80-inch lbs.
Step 8: Check all the connections and then connect back to the negative terminal of the battery.
Now this is the step, if you are looking for a visual demonstration of the process then check this Camshaft Position Sensor – 2004-2008 5.4L Ford F-150
We understand that the process can seem a bit overwhelming, so in that case you should consult the professionals. It should cost you around $100 to $135 with the part costing you about $45 to $60 and the labour cost being $60 to $75.
How to Diagnose and Verify the Multiple Cylinder Misfire Source?
Beyond the problems we have mentioned already, you can verify the source of the multiple-cylinder misfire through different tests and methods. Let’s go through each of these.
Is There Any Other Error Code?
Check this at the earliest. If you are searching for multiple cylinder misfires then chances are you faced the P0300 code. But look for other codes. This is crucial to problem-solving. Because if there is P0171 then there is a problem with the O2 sensor. So, check all the error codes you will get with the OBD2 scanner.
Is the Fuel Trim Reading Normal?
A short fuel trim number is between – 10% to +10% and long fuel trim number is between -5% to 5%. Grab your OBD2 scanner and see if the fuel trim number range is within this value. If it is then fuel trimming is happening properly and the accurate air-fuel mixture is maintained in the combustion chamber.
However, if the fuel trim reading is too negative then it means that the engine is running rich. But if the reading is too positive then the engine is running lean. Both of these will have an impact on the spark plug as already discussed and will lead to engine misfiring.
Is There Any Leaking Problem?
To confirm a leaking problem you need to carry out a test. This is the leakdown test where you introduce compressed air through the spark plug hole. Grab a leak down tester and follow the process of diagnosing the leaking problem.
- First, remove the spark plug and then rotate the engine until the piston reaches the top dead centre
- Now connect the tester gauge to the hole and then add 100 psi of compressed air into the cylinder
- Check the gauge reading of the tester. One will tell you about the pressure reading whereas the other shows how much air is leaving the cylinder.
- If the reading shows a pressure loss of five to ten per cent then it is running at an excellent condition,10-20% per cent means that the condition is still good but needs checking. But a loss of over 20 per cent requires an emergency check.
For a visual demonstration, follow this How To Perform A Leak Down Test – EricTheCarGuy video.
Is the Engine Compression Low?
You need to check the engine compression. Grab a compression tester and then follow these diagnosis steps.
- First, remove the spark plug and insert the compression tester in that place.
- Crank the engine, don’t start
- Now check the pressure reading on the gauge
- Finally, compare the reading with the optimal pressure and if it is low then there is a problem with the cylinder. You need to get the cylinder fixed as soon as possible.
This HOW TO TEST ENGINE CYLINDER COMPRESSION IN 15 MINUTES! is a good video to help you check engine compression.
FAQs
Can F150 Multiple Cylinder Misfire Happen on Diesel Engines?
Yes, f150 multiple-cylinder misfires can happen on diesel engines. Diesel engines are not immune from problems in their fuel system. Most of these problems lead to issues like engine stalling, rough idling and of course engine misfire.
Can a Bad O2 Sensor Cause Cylinder Misfire on Ford F150?
Yes, a bad O2 sensor can cause a cylinder misfire on Ford F150. If the O2 sensor is not working properly then it will give an incorrect signal. Because of this either more or less fuel will be added to the combustion chamber. If more fuel is added, the mixture will become rich and the spark plugs can get damaged. That can further lead to cylinder misfiring.
Can a Bad Battery Cause Misfire on Ford F150?
No, a bad battery will not cause misfires on the Ford F150. The battery helps to provide the necessary power to start the engine. With a damaged battery you will have problems starting. But engine misfire happens for other reasons related to spark plug, ignition coil, and issues in the overall fuel system.
Conclusion
With that the problems related to Ford F150 multiple cylinder misfires can be solved. All you need to do is look for the symptoms and diagnose the cylinder properly.
Once you confirm the source of the problem, make sure to solve the problem correctly. However, if you are not comfortable solving the problem on your own then you should consult the experts.
