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What should I check if my 2021 Toyota Highlander has poor fuel economy? - Toyota Highlander
Home/Cars/Toyota/Highlander/Fourth Generation (2020-present)/What should I check if my 2021 Toyota Highlander has poor fuel economy?

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

Toyota Highlander Fourth Generation (2020-present)

Error Codes
medium
Difficulty
medium
Severity
Navigation
ProblemSymptomsDiagnosisSolution
ProblemSymptomsDiagnosisSolution
3 min read
562 words

Problem Statement

Learn how to diagnose and fix poor fuel economy issues in your 2021 Toyota Highlander with our step-by-step guide.

Affected Component
Fuel system, Engine performance

Symptoms

  • •Noticeable decrease in miles per gallon (MPG) compared to manufacturer specifications.
  • •Engine warning light may be illuminated.
  • •Rough idling or engine performance issues.
  • •Poor acceleration or power loss.

Diagnostic Steps

  1. 1
  2. 2
  3. 3
  4. 4
  5. 5

Solution

💡 Expert Tip

For complex repairs like this, consider taking photos at each step. This helps if you need to reverse a step or consult with a mechanic. Also, keep all removed parts organized - you may need to reference them during reassembly.

Verification

After completing the repair, verify that the issue has been resolved:

  • ✓Test the affected component to ensure it functions correctly
  • ✓Check for any error codes or warning lights
  • ✓Monitor the vehicle for a few days to ensure the issue does not recur

Prevention Tips

To prevent this issue from occurring again:

  • •Follow the manufacturer's recommended maintenance schedule
  • •Address warning signs early before they develop into major issues
  • •Use quality parts and fluids recommended for your vehicle
  • •Keep detailed records of all repairs and maintenance

Tools & Equipment Required

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

Additional Information

Affected Component
Fuel system, Engine performance
Difficulty
medium
Severity
medium
Tools Required
6 items

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Back to Generation
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.