how to fix the engine performance issues on my Toyota Highlander XU70 (2020-Present)

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the battery to ensure safety while working on electrical components.

2. Addressing Diagnostic Codes

• Sub-steps:
  1. Refer to the OBD-II scanner and note any trouble codes.
  2. Research each code to understand the specific issues (e.g., P0300 for misfires).
  3. Clear the codes and take the vehicle for a test drive to see if they reappear.

3. Engine Oil Change

• Sub-steps:
  1. Remove the oil drain plug and allow old oil to drain completely.
  2. Replace the oil filter using an oil filter wrench.
  3. Add new engine oil as per manufacturer specifications (e.g., 0W-20).
  4. Reinstall the drain plug and torque it to 30 ft-lbs.

4. Air Filter Replacement

• Sub-steps:
  1. Open the hood and locate the air filter housing.
  2. Remove the screws/clamps holding the housing together.
  3. Replace the old air filter with a new one, ensuring it fits snugly.
  4. Reassemble the air filter housing.

5. Fuel System Inspection

• Sub-steps:
  1. Connect the fuel pressure gauge to the fuel rail.
  2. Turn the ignition to the "ON" position (do not start) to check the pressure.
  3. Compare the pressure reading to manufacturer specifications (typically around 50-60 psi).
  4. If low, inspect the fuel pump and fuel filter for clogs or failures.

6. Spark Plug Replacement

• Sub-steps:
  1. Remove the coil packs or spark plug wires from the spark plugs.
  2. Use a spark plug socket to remove old spark plugs.
  3. Check the gap on new spark plugs and adjust if necessary (usually 0.044 inches).
  4. Install new spark plugs and torque them to 13 ft-lbs.

7. Vacuum Leak Inspection

• Sub-steps:
  1. Visually inspect vacuum hoses for cracks or disconnections.
  2. Use carburetor cleaner and spray around suspected areas while the engine is running; listen for RPM changes.
  3. Replace any damaged hoses found during inspection.