how to resolve the check engine light and P0301 code on my Ford Explorer

Solution

1. Preparation

• Gather tools and parts required for the repair.
• Disconnect the negative battery terminal to prevent electrical shock.
• Allow the engine to cool before starting work.

2. Replace Spark Plug and Ignition Coil

1. Remove Engine Cover (if applicable)
   • Unscrew bolts securing the engine cover and lift it off.
2. Remove Ignition Coil
   • Unplug the electrical connector from the ignition coil.
   • Remove the bolt(s) securing the ignition coil using a socket set.
   • Gently pull the ignition coil out of the spark plug well.
3. Replace Spark Plug
   • Use a spark plug socket to remove the old spark plug from cylinder 1.
   • Inspect the old spark plug for damage or excessive wear.
   • Install a new spark plug, torqueing it to manufacturer specifications (typically around 13-15 ft-lbs).
4. Install New Ignition Coil
   • Insert the new ignition coil into the spark plug well.
   • Secure it with the bolt(s) and reconnect the electrical connector.

3. Check Fuel Injector

1. Test Fuel Injector
   • Use a noid light or multimeter to check for proper voltage and signal from the engine control unit (ECU) to the fuel injector.
   • If the injector is faulty, remove it by disconnecting the fuel line and electrical connector, then unscrewing it from the intake manifold.
   • Replace with a new fuel injector and reconnect all connections.

4. Verify Compression

1. Perform Compression Test
   • Remove the spark plug from cylinder 1.
   • Insert a compression gauge and crank the engine to measure compression.
   • Compare results to manufacturer specifications (typically around 150-200 psi).
   • If compression is low, investigate potential internal engine issues.

5. Reassemble and Test

• Reattach any components removed during the repair (engine cover, air intake).
• Reconnect the negative battery terminal.
• Start the engine and allow it to reach operating temperature.