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Home/Cars/Ford/F-150/12th Generation (2009-2014)/how to fix misfire code P0303 on Ford F-150 12th Generation (2009-2014)

how to fix misfire code P0303 on Ford F-150 12th Generation (2009-2014)

Ford F-150 12th Generation (2009-2014)

Error Codes
Severity: highDifficulty: mediumError Code: P03032-4 hours
4 min read
636 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 (2009-2014). Step-by-step guide with diagnostic procedures and repair instructions.

Error Code
P0303
Affected Component
Engine
Estimated Time
2-4 hours

Safety Warnings

  • ⚠Disconnect the battery before working on electrical components.
  • ⚠Allow the engine to cool before starting any repairs.

Symptoms

  • •Engine runs rough or unstable idle
  • •Check engine light illuminated
  • •Loss of power during acceleration
  • •Increased fuel consumption
  • •Engine stalling at low speeds
  • •Possible backfiring or popping sounds from the exhaust

Diagnostic Steps

  1. 1Scan the vehicle's onboard diagnostics using an OBD-II scanner to confirm the P0303 code.
  2. 2Inspect the ignition coil for cylinder 3 visually and check for any signs of damage or wear.
  3. 3Check the spark plug in cylinder 3 for fouling, wear, or incorrect gap.
  4. 4Perform a compression test on cylinder 3 to identify potential mechanical issues.
  5. 5Inspect fuel injector operation for cylinder 3 using a noid light or multimeter.
  6. 6Check for vacuum leaks in the intake manifold or around the throttle body that could affect cylinder 3.

Solution

Solution

1. Preparation

  • Gather tools and parts required.
  • Ensure the vehicle is parked on a flat surface and the engine is cool.
  • Disconnect the negative battery terminal to avoid electrical shorts.

2. Replace Spark Plug

  • Tools Required: Socket set, torque wrench, spark plug socket, anti-seize compound.
  • Remove the ignition coil from cylinder 3 by unscrewing the retaining bolt and disconnecting the electrical connector.
  • Use a spark plug socket to remove the old spark plug from cylinder 3.
  • Inspect the spark plug for wear; if damaged, replace it with a new spark plug that meets OEM specifications.
  • Apply a small amount of anti-seize compound to the threads of the new spark plug.
  • Install the new spark plug and torque it to the manufacturer's specification (typically around 13-15 lb-ft).
  • Reinstall the ignition coil and reconnect the electrical connector.

3. Replace Ignition Coil (if necessary)

  • Tools Required: Socket set, torque wrench.
  • If the ignition coil was found faulty during inspection, remove the coil from cylinder 3.
  • Install the new ignition coil by reversing the removal process.
  • Ensure it is securely fastened and reconnect the electrical connector.

4. Inspect and Replace Fuel Injector (if necessary)

  • Tools Required: Fuel injector removal tool, socket set, torque wrench.
  • If the fuel injector is suspected to be faulty, detach the fuel rail.
  • Remove the fuel injector from cylinder 3 and inspect it for clogs or damage.
  • Replace with a new OEM fuel injector if necessary.
  • Reassemble the fuel rail and reconnect all electrical connections.

5. Check for Vacuum Leaks

  • Visually inspect all vacuum hoses connected to the intake manifold, especially around cylinder 3.
  • Use a smoke machine or carburetor cleaner to detect any vacuum leaks.
  • Repair or replace any damaged hoses or gaskets.

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
  • •Fuel injector removal tool
  • •Multimeter

Parts Required

  • •Spark plug (for cylinder 3)
  • •Ignition coil (if necessary)
  • •Fuel injector (if necessary)

Additional Information

Error Code
P0303
Affected Component
Engine
Estimated Time
2-4 hours
Difficulty
medium
Severity
high
Tools Required
6 items
Parts Required
3 items

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