Vehicles using 3ZR-FE engine list:

Engine 3ZR-FE

Symptoms:
- Rough idling or hesitation during acceleration
- Decreased fuel efficiency
- Engine misfires or stalling
- Check Engine Light (CEL) illumination
- Unusual engine noises such as ticking or knocking

Diagnosis:
- Use an OBD-II scanner to check for stored fault codes related to ignition, fuel, or emission systems.
- Inspect spark plugs and ignition coils for wear or damage, as these are common failure points.
- Check for vacuum leaks around intake manifold gaskets and hoses, which can cause rough idling.
- Examine the fuel injectors for clogging or malfunction.
- Perform a compression test to rule out internal engine wear or valve issues.
- Inspect timing chain condition and tensioner, as timing chain noise or stretch can cause performance issues.

Fixes:
- Replace worn or fouled spark plugs and faulty ignition coils to restore proper combustion.
- Repair or replace damaged vacuum hoses and intake manifold gaskets to eliminate leaks.
- Clean or replace clogged fuel injectors to ensure proper fuel delivery.
- Replace timing chain and tensioner if excessive wear or noise is detected.
- Address any detected sensor faults, such as mass airflow sensor or oxygen sensors, by cleaning or replacement.
- Regular oil changes with recommended grade oil to maintain proper lubrication and prevent premature wear.

Prevention:
- Follow Toyota’s recommended maintenance schedule, especially for spark plug replacement every 100,000 km or as specified.
- Use high-quality fuel and oil to reduce deposits and wear.
- Regularly inspect and replace air filters to ensure clean airflow.
- Monitor engine performance and address any warning signs early to prevent more severe damage.
- Maintain timely oil changes to protect timing chain components and reduce engine wear.
- Avoid prolonged idling and aggressive driving to reduce stress on engine components.

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