how to fix P0303 misfire code in Ford F-150 13th Generation (2015-2020)

Ford F-150 13th Generation (2015-2020)

Error Codes

2-4 hours

Time

medium

Difficulty

high

Severity

Error Code: P0303

3 min read

597 words

⚠️ Safety Warning

This issue requires immediate attention. If you are not experienced with automotive repairs, consult a professional mechanic. Working on critical systems can be dangerous.

Problem Statement

Learn how to diagnose and fix P0303 cylinder 3 misfire in Ford F-150 (2015-2020). Step-by-step guide with diagnostic procedures and repair instructions.

Error Code

P0303

Affected Component

Engine

Estimated Time

2-4 hours

⚠️ Safety Warnings

Important safety information - read before proceeding

•Disconnect battery before working on electrical systems.
•Allow engine to cool before opening components related to the fuel or ignition systems.

Symptoms

•Check engine light illuminated
•Rough idle or engine shake
•Decreased acceleration and power
•Poor fuel economy
•Increased exhaust emissions

Diagnostic Steps

1
Scan the vehicle's computer using an OBD-II scanner to confirm the P0303 code.
2
Inspect the spark plug and ignition coil for cylinder 3 for signs of wear or damage.
3
Check the condition of the fuel injector for cylinder 3.
4
Perform a compression test on cylinder 3 to check for mechanical issues.
5
Inspect vacuum lines and intake manifold for leaks that might affect cylinder 3.
6
Examine the wiring and connectors to the ignition coil and fuel injector for damage or corrosion.

Solution

💡 Expert Tip

For complex repairs like this, consider taking photos at each step. This helps if you need to reverse a step or consult with a mechanic. Also, keep all removed parts organized - you may need to reference them during reassembly.

Verification

After completing the repair, verify that the issue has been resolved:

✓Test the affected component to ensure it functions correctly
✓Check for any error codes or warning lights
✓Monitor the vehicle for a few days to ensure the issue does not recur

Prevention Tips

To prevent this issue from occurring again:

•Follow the manufacturer's recommended maintenance schedule
•Address warning signs early before they develop into major issues
•Use quality parts and fluids recommended for your vehicle
•Keep detailed records of all repairs and maintenance

Tools & Equipment Required

•OBD-II scanner
•Socket set
•Torque wrench
•Spark plug socket
•Multimeter
•Fuel injector cleaning kit

Parts Required

•Spark plug (specific to Ford F-150)
•Ignition coil (specific to cylinder 3)
•Fuel injector (if cleaning is not sufficient)

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Diagnostic Steps

1
Scan the vehicle's computer using an OBD-II scanner to confirm the P0303 code.
2
Inspect the spark plug and ignition coil for cylinder 3 for signs of wear or damage.
3
Check the condition of the fuel injector for cylinder 3.
4
Perform a compression test on cylinder 3 to check for mechanical issues.
5
Inspect vacuum lines and intake manifold for leaks that might affect cylinder 3.
6
Examine the wiring and connectors to the ignition coil and fuel injector for damage or corrosion.

Solution

1. Preparation

Gather tools and parts needed for repair.
Disconnect the negative battery terminal to prevent electrical shorts.
Allow the engine to cool down if it has been running.

2. Inspect and Replace Spark Plug

Tools Required: Socket set, torque wrench, spark plug socket.
Remove the ignition coil from cylinder 3 by unbolting it and disconnecting the electrical connector.
Remove the spark plug using the spark plug socket. Inspect it for wear, carbon buildup, or damage.
If necessary, replace the spark plug with a new one, ensuring it is gapped to manufacturer specifications (typically around 0.030-0.035 inches).
Reinstall the ignition coil and reconnect the electrical connector.

3. Inspect and Replace Ignition Coil

If the spark plug is in good condition, test the ignition coil for proper operation using a multimeter.
If the ignition coil is faulty, remove the old coil and replace it with a new one.
Ensure the new coil is seated properly and reconnect the electrical connector.

4. Inspect and Clean Fuel Injector

If ignition components are in good condition, check the fuel injector for cylinder 3.
Disconnect the fuel injector connector and remove the injector from the rail.
Clean the injector using a fuel injector cleaning kit or replace it if necessary.
Reinstall the injector and reconnect the electrical connector.

5. Reassemble and Test

Reconnect the negative battery terminal.
Start the engine and allow it to idle. Monitor for any misfire codes or symptoms.
Conduct a road test to ensure the performance has returned to normal.