how to fix P0303 misfire code on a Ford Explorer Fifth Generation (2011-2019)

Ford Explorer Fifth Generation (2011-2019)

Error Codes

2-4 hours

Time

medium

Difficulty

high

Severity

Error Code: P0303

4 min read

635 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 Explorer (2011-2019). 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 the battery before performing electrical repairs.
•Allow the engine to cool before working on components to prevent burns.

Symptoms

•Check engine light illuminated
•Rough idle or shaking during idle
•Loss of power during acceleration
•Decreased fuel efficiency
•Engine stalling or hesitation
•Unusual noise from the engine compartment

Diagnostic Steps

1
Scan the vehicle with an OBD-II scanner to confirm the P0303 code and check for any additional codes.
2
Inspect the ignition coil for cylinder 3 for signs of damage or wear.
3
Check the spark plug in cylinder 3 for condition, gap, and carbon buildup.
4
Perform a compression test on cylinder 3 to assess the engine's internal condition.
5
Inspect fuel injectors for proper operation and ensure there are no clogs.
6
Check for vacuum leaks around the intake manifold and vacuum hoses.

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
•Fuel injector removal tool

Parts Required

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

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Diagnostic Steps

1
Scan the vehicle with an OBD-II scanner to confirm the P0303 code and check for any additional codes.
2
Inspect the ignition coil for cylinder 3 for signs of damage or wear.
3
Check the spark plug in cylinder 3 for condition, gap, and carbon buildup.
4
Perform a compression test on cylinder 3 to assess the engine's internal condition.
5
Inspect fuel injectors for proper operation and ensure there are no clogs.
6
Check for vacuum leaks around the intake manifold and vacuum hoses.

Solution

1. Preparation

Gather tools and parts required for the repair.
Disconnect the negative battery terminal to prevent electrical shock.

2. Replace Ignition Coil

Remove Engine Cover (if applicable)
- Use a socket set to remove any screws securing the engine cover.
Disconnect Ignition Coil Connector
- Press the tab and pull the connector off the ignition coil for cylinder 3.
Remove Ignition Coil
- Unbolt the ignition coil using the appropriate socket size.
- Gently pull the ignition coil from the spark plug well.
Install New Ignition Coil
- Place the new ignition coil in the spark plug well and secure with bolts to manufacturer specifications (typically 10-12 ft-lbs).
Reconnect Coil Connector
- Plug the connector back onto the new ignition coil.

3. Replace Spark Plug

Remove Spark Plug
- Use a spark plug socket to remove the spark plug from cylinder 3.
Inspect and Clean
- Check for wear, carbon deposits, or damage; clean if necessary.
Install New Spark Plug
- Gap the new spark plug to manufacturer specifications (typically 0.054 inches).
- Screw in the new spark plug and tighten to a torque of 12-15 ft-lbs.

4. Inspect Fuel Injector

Remove Fuel Injector Connector
- Unplug the electrical connector from the fuel injector for cylinder 3.
Remove Fuel Injector
- Remove any retaining clips and pull out the fuel injector.
Install New Fuel Injector
- Apply a small amount of engine oil to the O-ring of the new fuel injector.
- Insert the new injector and secure it with clips.

5. Check for Vacuum Leaks

Inspect all hoses and the intake manifold for any cracks or loose connections and replace or repair as necessary.