Problem Statement
Learn how to diagnose and fix rough idle issues in your Toyota Highlander. Step-by-step guide with diagnostic procedures and repair instructions.

Toyota Highlander Fourth Generation (2020-present)
Learn how to diagnose and fix rough idle issues in your Toyota Highlander. Step-by-step guide with diagnostic procedures and repair instructions.
Important safety information - read before proceeding
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.
After completing the repair, verify that the issue has been resolved:
To prevent this issue from occurring again:
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Remove Engine Cover: If applicable, remove any plastic engine covers to access the spark plugs.
Remove Old Spark Plugs: Use a spark plug socket to carefully remove each spark plug.
Install New Spark Plugs: Gap new spark plugs as per manufacturer specifications and install them, tightening to the specified torque.
Remove Fuel Rail: Detach the fuel rail from the engine, being careful to avoid fuel spillage.
Clean Injectors: Use a fuel injector cleaning kit to flush out any deposits.
Reinstall Fuel Rail: Reattach the fuel rail and ensure all connections are secure.