FAULTBASE
Error CodesASKCars
© 2026 FAULTBASE
All rights reserved.
v2.0.0 • Production
ContactPrivacyImpressum
my Toyota Highlander has a rough idle when stopped what could be wrong - Toyota Highlander
Home/Cars/Toyota/Highlander/Third Generation (2014-2019)/my Toyota Highlander has a rough idle when stopped what could be wrong

my Toyota Highlander has a rough idle when stopped what could be wrong

Toyota Highlander Third Generation (2014-2019)

Error Codes
2-4 hours
Time
medium
Difficulty
medium
Severity
Navigation
ProblemSymptomsDiagnosisSolution
ProblemSymptomsDiagnosisSolution
3 min read
533 words

Problem Statement

Learn how to diagnose and fix rough idle issues in Toyota Highlander. Step-by-step guide with symptoms, diagnostic steps, and repair instructions.

Affected Component
Engine
Estimated Time
2-4 hours

⚠️ Safety Warnings

Important safety information - read before proceeding

  • •Disconnect the battery before working on electrical components.
  • •Allow the engine to cool before attempting to work on it.

Symptoms

  • •Check engine light illuminated
  • •Engine stalling occasionally
  • •Increased fuel consumption
  • •Vibrations felt within the cabin
  • •Poor acceleration response when starting from a stop

Diagnostic Steps

  1. 1
  2. 2
  3. 3
  4. 4
  5. 5
  6. 6

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
  • •Socket set
  • •Fuel pressure gauge
  • •Throttle body cleaner
  • •Soft brush

Parts Required

  • •Air filter
  • •Spark plugs
  • •Ignition coils (if needed)
  • •Vacuum hoses (if needed)

Additional Information

Affected Component
Engine
Estimated Time
2-4 hours
Difficulty
medium
Severity
medium
Tools Required
5 items
Parts Required
4 items

Related Faults

Loading...

Share this solution

Comments

Sign in to share your thoughts

Sign In

No comments yet

Be the first to share your thoughts

Back to Generation
Solution
1. Preparation
  • Gather necessary tools and parts.
  • Disconnect the negative battery terminal to prevent electrical shorts.
  • Allow the engine to cool down before starting work.
2. Replace Air Filter
  • Locate the air filter housing.
  • Open the housing by releasing the clips or screws.
  • Remove the old air filter and install a new one, ensuring it fits securely.
  • Reassemble the air filter housing.
3. Check and Replace Spark Plugs
  • Remove the ignition coil(s) by unscrewing the bolts and pulling them off the spark plugs.
  • Use a socket wrench to remove the old spark plugs.
  • Inspect the old plugs for wear; replace with new spark plugs according to manufacturer specifications (typically NGK or Denso).
  • Reinstall the ignition coils and securely fasten them.
4. Inspect and Clean IAC Valve
  • Locate the IAC valve (usually near the throttle body).
  • Disconnect the electrical connector and remove the IAC valve using a socket wrench.
  • Clean the valve with throttle body cleaner and a soft brush to remove carbon buildup.
  • Reinstall the valve and reconnect the electrical connector.
5. Test and Replace Vacuum Hoses if Necessary
  • Visually inspect all vacuum hoses for cracks or disconnections.
  • Replace any damaged hoses with new ones, ensuring a snug fit.
  • Use a smoke test if available to detect any hidden leaks in the vacuum system.