why does my Toyota Highlander Third Generation (2014-2019) have poor fuel economy

Solution

1. Preparation

• Tools Required: OBD-II scanner, socket set, torque wrench, multimeter, fuel pressure gauge.
• Ensure the vehicle is parked on a flat surface, and the engine is cool.
• Disconnect the battery to prevent electrical shorts.

2. Addressing Engine Codes

• Sub-steps:
  1. Connect the OBD-II scanner and retrieve any stored error codes.
  2. Research codes to determine the underlying issues (e.g., P0171 for lean condition).
  3. Clear codes after repairs to ensure no further issues are present.

3. Replace Air Filter

• Sub-steps:
  1. Locate the air filter housing and open it by unclipping or unscrewing.
  2. Remove the old air filter and inspect the housing for debris.
  3. Install the new air filter, ensuring it is seated correctly.
  4. Reassemble the housing and secure it.

4. Inspect and Replace Spark Plugs

• Sub-steps:
  1. Remove the ignition coils by unscrewing and disconnecting the electrical connectors.
  2. Unscrew the old spark plugs using a socket wrench and inspect them for wear.
  3. Install new spark plugs, tightening them to the manufacturer’s specified torque (usually around 13-15 ft-lbs).
  4. Reconnect the ignition coils securely.

5. Check and Repair Fuel System

• Sub-steps:
  1. Inspect fuel lines for leaks or damage, replacing any faulty sections.
  2. Test the fuel pressure with a gauge to ensure it is within specifications (usually 50-60 psi).
  3. If the fuel pump is faulty, replace it following manufacturer guidelines for removal and installation.