What should I check if my 2021 Toyota Highlander has poor fuel economy?

Troubleshooting Poor Fuel Economy in a 2021 Toyota Highlander (Fourth Generation)

Tools Required

• OBD-II Scanner
• Tire pressure gauge
• Basic hand tools (screwdrivers, wrenches)
• Torque wrench
• Fuel pressure gauge (optional)
• Multimeter (for electrical diagnostics)

Repair Instructions

1. Address Tire Issues

   • Tire Pressure: Inflate tires to the recommended level.
   • Alignment: If tires are unevenly worn, schedule a wheel alignment.
   • Rotation: Rotate tires as per manufacturer recommendations.

2. Replace Air Filter

   • Open the air filter box and remove the old filter.
   • Install a new OEM or high-quality aftermarket air filter.
   • Ensure the filter is seated properly and secure the air filter box.

3. Inspect and Clean the Mass Air Flow (MAF) Sensor

   • Locate the MAF sensor (usually between the air filter and throttle body).
   • Disconnect the electrical connector and remove the sensor.
   • Clean the sensor with MAF sensor cleaner and reinstall it.

4. Check Fuel System

   • If DTCs indicate fuel system problems, inspect fuel injectors for clogs or leaks.
   • Consider using a fuel system cleaner if injectors are dirty.
   • Fuel Filter: If applicable, replace the fuel filter as per the maintenance schedule.

5. Perform Engine Tune-Up

   • Replace spark plugs if they show signs of wear or if they are past the replacement interval.
   • Inspect ignition coils and wiring for damage.
   • Confirm that the engine is properly timed and running smoothly.

6. Check for Exhaust Restrictions

   • Inspect the exhaust system for blockages or damage.
   • Check the catalytic converter for signs of clogging or failure.

7. Monitor and Test Drive

   • After completing repairs, reset the trip computer and take the vehicle for a test drive.
   • Monitor fuel economy over the next few tankfuls to assess improvements.

Conclusion

If poor fuel economy persists after performing the above checks and repairs, it may be advisable to have the vehicle evaluated by a professional technician with specialized diagnostic equipment. Ongoing issues may indicate deeper mechanical problems that need expert attention.