how to fix my Toyota Camry that has a rough idle when cold?

Solution

1. Preparation

• Gather necessary tools and parts.
• Park the vehicle on a level surface and engage the parking brake.
• Disconnect the negative battery terminal to prevent electrical shorts.

2. Inspect and Replace Spark Plugs

• Remove the ignition coils (if applicable) using a socket set.
• Take out the spark plugs with a spark plug socket.
• Inspect for wear or carbon deposits; replace with OEM-spec spark plugs if necessary.
• Reinstall the spark plugs and ignition coils, torquing to manufacturer specifications.

3. Clean the Throttle Body

• Remove the air intake duct leading to the throttle body.
• Use throttle body cleaner and a soft cloth to clean the throttle plate and surrounding areas.
• Ensure the throttle plate moves freely after cleaning.
• Reattach the air intake duct securely.

4. Check Fuel System

• Connect a fuel pressure gauge to the fuel rail.
• Start the engine and observe fuel pressure; it should meet manufacturer specifications.
• If pressure is low, inspect the fuel filter and replace if clogged, or check the fuel pump for failure.
• Reconnect any lines or components as necessary.

5. Inspect for Vacuum Leaks

• Visually check hoses and connections for cracks or disconnections.
• Use a smoke machine or carburetor cleaner around suspected areas to detect leaks.
• Replace any damaged hoses or connectors.