NGK Iridium IX Spark Plugs TR55IX 6-Pack — Fine-Wire Iridium Electrodes for Longer Life

NGK 7164 Iridium IX TR55IX spark plugs are a six-pack of OEM-quality iridium electrodes designed to deliver reliable ignition performance and long service life.

Built for drivers and technicians who want factory-level fit and dependable starts, these NGK Iridium IX plugs use a fine-wire iridium center electrode to improve ignitability and extend replacement intervals compared with standard plugs. As the world’s largest OEM spark plug supplier, NGK engineers these plugs to meet original equipment specifications for many applications, but fit should be confirmed using NGK’s application guide before ordering.

Why choose NGK Iridium IX over conventional spark plugs?

Iridium is harder and finer than conventional nickel electrodes, which allows a smaller center electrode and a stronger spark under the same conditions. That combination improves combustion consistency, helps maintain throttle response, and resists wear for longer intervals between changes.

• Fine-wire iridium center electrode for improved spark formation
• Higher wear resistance versus nickel plugs for extended life
• Designed to meet OEM dimensions and heat range expectations

How do these plugs affect engine performance and reliability?

Proper ignition helps the engine run smoothly, supports efficient fuel burn, and reduces misfires caused by electrode degradation. NGK Iridium IX plugs are engineered to preserve spark energy and consistency as they age, which helps maintain drivability through the service interval.

• Consistent spark delivery to reduce hesitation and misfires
• Durable construction minimizes electrode erosion over time
• Corrosion-resistant materials for stable long-term performance

What should I check before buying to ensure correct fitment?

NGK supplies many original-equipment configurations, but fitment depends on engine model, drivetrain and vehicle production year. Always verify the NGK part number against the vehicle application chart or your owner’s manual to confirm the correct plug type and required quantity.

• Confirm NGK part number 7164 / TR55IX in the NGK application database
• Match gap specifications and thread dimensions for your engine
• Order the correct quantity—this listing includes six spark plugs

How should these plugs be installed and maintained?

Install plugs to the manufacturer’s torque specification and check the pre-set gap where applicable. Use proper anti-seize only if recommended for your engine and retighten after the initial warm-up if specified by the vehicle maker.

• Torque to vehicle manufacturer recommendations to avoid thread damage
• Check and adjust gap only if the application requires it
• Replace plugs as part of scheduled maintenance intervals or if ignition issues appear

Who is this for? The NGK 7164 Iridium IX TR55IX 6-pack is aimed at vehicle owners, fleet managers, and mechanics who want OEM-level spark plug quality with the longevity benefits of iridium. It’s a smart choice for those servicing cars or light trucks that specify NGK Iridium IX in their maintenance schedules and for anyone seeking a plug that balances reliable ignition, longer service life, and parts compatibility. Remember to confirm compatibility with your specific vehicle before purchasing to ensure correct fitment and optimal performance.