Step 1: Gather Necessary Tools and Materials
 

• Spark plug socket
• Socket wrench
• Torque wrench
• Extension bar (optional)
• Gap gauge
• New spark plugs
• Anti-seize compound (optional)
• Dielectric grease (optional)
• Safety gloves and goggles

 
Step 2: Prepare Your Vehicle
 

• Ensure the vehicle is parked on a flat surface and the engine is cool.
• Open the hood and disconnect the negative battery terminal for safety.

 
Step 3: Locate the Spark Plugs
 

• Identify the location of the spark plugs. In a 2016 Toyota RAV4, the spark plugs are located underneath the engine cover.
• Carefully remove the engine cover by pulling it up from the edges; it should come off easily as it’s held by clips.

 
Step 4: Remove Ignition Coils
 

• Disconnect the electrical connector from the ignition coil by pressing the tab and pulling it apart.
• Remove the bolt securing the ignition coil to the engine using a socket wrench.
• Gently pull the ignition coil straight out to access the spark plug.

 
Step 5: Remove Old Spark Plugs
 

• Attach the spark plug socket to the wrench, possibly with an extension bar, and carefully remove the spark plug by turning it counterclockwise.
• Inspect the old spark plug for any signs of unusual wear or damage, which could indicate underlying engine issues.

 
Step 6: Prepare New Spark Plugs
 

• Check the gap of the new spark plugs using the gap gauge to ensure they match the specifications outlined in the owner's manual. Adjust the gap if necessary.
• Apply a small amount of anti-seize compound to the threads of the spark plug to prevent it from seizing in the engine (optional).

 
Step 7: Install New Spark Plugs
 

• Carefully thread the new spark plug into the engine by hand to avoid cross-threading.
• Once hand-tight, use the socket wrench to turn the spark plug until it is snug. Be cautious not to overtighten.
• Torque the spark plug to the manufacturer's specifications using a torque wrench.

 
Step 8: Reinstall Ignition Coils
 

• Place the ignition coil back over the new spark plug and press it down firmly.
• Secure the ignition coil with the bolt and reconnect the electrical connector.
• Repeat the removal and installation process for each spark plug.

 
Step 9: Reattach the Engine Cover
 

• Carefully position the engine cover back over the engine and press it down to snap it back into place.

 
Step 10: Reconnect Battery
 

• Reconnect the negative battery terminal to restore electrical power to the vehicle.

 
Step 11: Test the Vehicle
 

• Start the engine to ensure that it runs smoothly and without misfires.
• If there are no issues, you have successfully changed the spark plugs.