my Toyota Highlander XU70 (2020-Present) has a rough start in the morning

Solution

1. Preparation

• Gather tools and parts.
• Disconnect the negative battery terminal to prevent electrical shorts.
• Allow the engine to cool if it has been running.

2. Battery Inspection and Replacement

• Tools Required: Multimeter, socket set
  • 1. Use a multimeter to check the battery voltage; it should be above 12.4 volts.
  • 1. If the voltage is low, charge or replace the battery as necessary.
  • 1. Clean battery terminals with a wire brush and reconnect securely.

3. Fuel System Inspection

• Tools Required: Fuel pressure gauge, socket set
  • 1. Locate the fuel pressure test port on the fuel rail.
  • 1. Attach the fuel pressure gauge and turn the ignition to the "on" position without starting the engine.
  • 1. Check that the pressure meets manufacturer specifications (typically 30-50 psi for this model).
  • 1. If pressure is low, check the fuel pump and filter for issues and replace as necessary.

4. Ignition System Inspection

• Tools Required: Socket set, spark plug socket, torque wrench
  • 1. Remove the engine cover to access the ignition coils and spark plugs.
  • 1. Inspect spark plugs for wear, carbon buildup, or damage; replace if necessary.
  • 1. Check ignition coils for proper operation; replace any faulty coils.
  • 1. Reinstall spark plugs and coils, ensuring proper torque specifications (typically around 13 lb-ft for spark plugs).

5. Air Intake and Sensors

• Tools Required: Screwdriver set, cleaning solution
  • 1. Inspect the air intake hose and MAF for leaks or obstructions.
  • 1. Clean the MAF sensor using a dedicated MAF cleaner.
  • 1. Reassemble the intake system securely.