Why does my 2023 Toyota Highlander have a rough idle?

Rough Idle Diagnosis for 2023 Toyota Highlander

Repair Instructions:

1. Addressing Fault Codes:

   • If DTCs are present, follow the manufacturer’s recommended diagnostics for each code. This may involve replacing faulty sensors, wiring, or components.

2. Replacing Spark Plugs:

   • Remove the ignition coils and spark plugs using the spark plug socket.
   • Install new spark plugs according to the manufacturer’s specifications (proper torque settings).
   • Reconnect ignition coils securely.

3. Cleaning MAF and Throttle Body:

   • Use a MAF cleaner to gently clean the MAF sensor.
   • Remove the throttle body and clean it using throttle body cleaner, ensuring the butterfly valve operates smoothly.

4. IAC Valve Replacement:

   • If the IAC valve is determined to be faulty, disconnect the electrical connector and remove the mounting screws.
   • Install the new IAC valve and reconnect the electrical connector.

5. Fuel Injector Service:

   • If fuel injectors are clogged, consider using a fuel injector cleaning service or replace them if necessary.

6. Final Checks:

   • After repairs, clear any stored DTCs with the OBD-II scanner.
   • Start the engine and allow it to reach operating temperature; monitor idle quality.
   • Test drive the vehicle to ensure smooth operation under varying conditions.

Conclusion:

If the rough idle persists after following the above steps, it may be advisable to consult with a certified Toyota technician for further diagnosis, as issues can sometimes be complex or require specialized equipment.