my Toyota Camry XV40 has a rough idle when cold what's the cause

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the negative battery terminal to ensure safety.

2. Clean or Replace MAF Sensor

• Remove the MAF sensor from the intake duct using a socket set.
• Clean the MAF sensor using a dedicated MAF cleaner; do not touch the sensor element.
• Reinstall the MAF sensor and reconnect the electrical connector.

3. Inspect and Clean Throttle Body

• Remove the air intake duct to access the throttle body.
• Use throttle body cleaner and a soft cloth to clean the throttle plate and body.
• Ensure the throttle plate moves freely and is properly calibrated.
• Reassemble the intake duct securely.

4. Replace Intake Air Temperature Sensor (if faulty)

• Locate the intake air temperature sensor on the intake manifold.
• Disconnect the electrical connector and remove the sensor using a socket wrench.
• Install the new sensor and reconnect the electrical connection.

5. Check and Repair Vacuum Leaks

• Inspect all vacuum lines for cracks or disconnections.
• Replace any damaged hoses or re-secure loose connections.
• Perform a smoke test if necessary to locate hidden leaks.

6. Verify Fuel Pressure

• Connect a fuel pressure gauge to the fuel rail.
• Turn the ignition to the ON position (without starting) and check the pressure reading.
• Compare the reading to the manufacturer’s specifications; replace the fuel pump if it’s below specifications.