my Honda Civic 9th Generation (2012-2015) has a rough idle, what could be wrong?

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the battery to ensure safety while working on electrical components.

2. Inspect and Replace Spark Plugs

• Remove the engine cover if necessary.
• Using a socket set, carefully unscrew and remove the spark plugs.
• Inspect the spark plugs for wear, carbon buildup, or damage.
• Replace with new spark plugs as per manufacturer specifications (typically NGK or Denso for Honda).
• Torque the new spark plugs to the manufacturer's specification (usually around 13 lb-ft).

3. Clean the Throttle Body

• Remove the air intake duct connected to the throttle body.
• Use throttle body cleaner and a soft cloth to clean the throttle plate and surrounding areas.
• Ensure no cleaner residue enters the intake manifold.
• Reattach the air intake duct securely once cleaning is complete.

4. Check and Repair Vacuum Leaks

• Inspect all vacuum lines for cracks or disconnections.
• Replace any damaged vacuum hoses.
• Use a smoke machine or carburetor cleaner around vacuum line connections to identify leaks.

5. Fuel System Inspection

• Connect a fuel pressure gauge to the fuel rail to check pressure.
• If the pressure is low, inspect the fuel filter and fuel pump for clogs or failure.
• Replace the fuel filter if necessary; if the pump is faulty, replace it following the manufacturer’s instructions.

6. Final Assembly and Testing

• Reconnect the battery.
• Start the engine and allow it to reach operating temperature while monitoring for any abnormal sounds or behaviors.
• Check for any new error codes with the OBD-II scanner.