how to fix P0303 misfire code on my 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

4 min read

692 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 the negative battery terminal to prevent electrical short circuits.
•Allow the engine to cool down before beginning work.

Symptoms

•Check engine light illuminated
•Rough idle or engine shaking
•Decreased acceleration and power
•Poor fuel economy
•Engine stalling or hesitation during acceleration

Diagnostic Steps

1
Scan for error codes using OBD-II scanner to confirm P0303 and check for additional codes.
2
Inspect the ignition coil for cylinder 3 visually for any signs of damage or wear.
3
Check the spark plug in cylinder 3 for fouling, wear, or incorrect gap.
4
Perform a compression test on cylinder 3 to evaluate engine health.
5
Inspect fuel injector for cylinder 3 for clogs or electrical issues.
6
Verify vacuum leaks or intake manifold gasket integrity in the vicinity of cylinder 3.

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
•Gap gauge
•Compression tester
•Multimeter
•Fuel injector cleaner

Parts Required

•Ignition coil (if faulty)
•Spark plug (if worn)
•Fuel injector (if clogged)
•Intake manifold gasket (if leaking)

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Diagnostic Steps

1
Scan for error codes using OBD-II scanner to confirm P0303 and check for additional codes.
2
Inspect the ignition coil for cylinder 3 visually for any signs of damage or wear.
3
Check the spark plug in cylinder 3 for fouling, wear, or incorrect gap.
4
Perform a compression test on cylinder 3 to evaluate engine health.
5
Inspect fuel injector for cylinder 3 for clogs or electrical issues.
6
Verify vacuum leaks or intake manifold gasket integrity in the vicinity of cylinder 3.

Solution

1. Preparation

Gather necessary tools and parts.
Disconnect the negative battery terminal to prevent electrical short circuits.
Allow the engine to cool down before beginning work.

2. Inspect and Replace Ignition Coil (if necessary)

Tools Required: Socket set, torque wrench.
Sub-steps:
1. Remove the engine cover if applicable.
2. Disconnect the wiring harness from the ignition coil on cylinder 3.
3. Remove the bolts securing the ignition coil using a socket.
4. Pull the ignition coil out of the spark plug well.
5. Install the new ignition coil and secure it with bolts, torquing to manufacturer specifications (usually around 10-15 lb-ft).
6. Reconnect the wiring harness.

3. Inspect and Replace Spark Plug (if necessary)

Tools Required: Spark plug socket, gap gauge, torque wrench.
Sub-steps:
1. Remove the ignition coil from cylinder 3 (refer to the previous step).
2. Use a spark plug socket to remove the spark plug by turning counterclockwise.
3. Inspect the spark plug for signs of wear or fouling. Check the gap using a gap gauge and adjust if necessary (typically around 0.050 inches).
4. Install a new spark plug, hand-tightening it, then torque to the manufacturer’s specification (usually around 12-15 lb-ft).
5. Reinstall the ignition coil.

4. Inspect and Clean Fuel Injector (if necessary)

Tools Required: Fuel injector cleaner, multimeter (for electrical testing).
Sub-steps:
1. Disconnect the fuel line and electrical connector from the fuel injector on cylinder 3.
2. Remove the fuel injector using the appropriate tools.
3. Clean the injector using a fuel injector cleaner or replace it if it is clogged.
4. Test the injector with a multimeter for proper resistance (typically 12-16 ohms).
5. Reinstall the cleaned or new fuel injector ensuring proper sealing.

5. Perform a Compression Test (if necessary)

Tools Required: Compression tester.
Sub-steps:
1. Remove the spark plug from cylinder 3.
2. Insert the compression tester into the spark plug hole.
3. Crank the engine for several seconds and record the compression reading.
4. Compare the reading to the manufacturer’s specifications (usually around 120-150 psi).
5. If compression is low, further investigation into internal engine issues is required.