why does my Toyota RAV4 have a P0301 code for cylinder 1 misfire

Solution

1. Preparation

• Gather necessary tools and ensure the vehicle is parked on a level surface with the engine off.
• Disconnect the negative battery terminal.

Tools Required:

• OBD-II scanner
• Socket set
• Torque wrench
• Compression tester
• Multimeter

2. Replace Spark Plug

• Remove the ignition coil from cylinder 1.
• Unscrew and remove the spark plug using a socket wrench.
• Inspect the spark plug threads for carbon buildup; clean if necessary.
• Install a new spark plug, ensuring it is gapped correctly to manufacturer specifications.
• Torque the spark plug to the manufacturer's specified value (typically around 13-15 lb-ft).

3. Check and Replace Ignition Coil

• Disconnect the electrical connector from the ignition coil.
• Remove the ignition coil from cylinder 1.
• Test the ignition coil with a multimeter to check for proper resistance; replace if outside specifications.
• Install the new ignition coil and reconnect the electrical connector.

4. Inspect and Clean Fuel Injector

• Disconnect the fuel injector connector for cylinder 1.
• Remove the fuel injector using the appropriate tools.
• Clean the injector with a fuel injector cleaner or replace if clogged or damaged.
• Reinstall the fuel injector and reconnect the electrical connector.

5. Perform Compression Test

• Remove the spark plug and ignition coil from cylinder 1.
• Insert the compression tester into the spark plug hole.
• Crank the engine several times and note the compression reading. Compare it to specifications.
• If compression is low, further investigation into piston rings, valves, or head gasket may be necessary.