why does my Toyota Camry XV40 (2007-2011) have a rough idle when cold

Solution

1. Preparation

• Gather tools and parts required for the repair.
• Ensure the vehicle is parked on a level surface and the engine is cool.
• Disconnect the negative battery terminal to prevent electrical shorts.

2. Inspect and Replace Spark Plugs

• Remove the ignition coil cover using a socket set.
• Disconnect the ignition coils and remove them.
• Extract the spark plugs using a spark plug socket.
• Inspect the spark plugs for wear; replace with OEM specifications if necessary.
• Reinstall the spark plugs and ignition coils, ensuring proper torque (typically 13-15 ft-lbs).

3. Clean or Replace the Idle Air Control Valve (IAC)

• Locate the IAC on the throttle body.
• Disconnect the electrical connector and remove the mounting screws.
• If cleaning, use throttle body cleaner to remove carbon deposits; if faulty, replace with a new unit.
• Reinstall the IAC and reconnect the electrical connector.

4. Replace the Engine Coolant Temperature Sensor (if faulty)

• Locate the coolant temperature sensor on the engine.
• Disconnect the wiring harness and remove the sensor using a socket.
• Apply thread sealant on the new sensor, install it, and reconnect the wiring harness.

5. Inspect and Clean the Throttle Body

• Remove the air intake duct to access the throttle body.
• Use throttle body cleaner to clean the inside of the throttle body.
• Reinstall the intake duct securely.