NGK Iridium IX Spark Plugs LFR5AIX-11 (6 Pack) — Iridium Tip, Pre-Gapped .044" for V6 Engines

NGK 4469 Iridium IX spark plugs (LFR5AIX-11) are high-performance iridium-tipped replacement plugs sold in a 6-pack and engineered for reliable ignition, improved throttle response, and long service life.

These LFR5AIX-11 plugs combine a fine-wire iridium center electrode, copper core, and ceramic insulator to deliver consistent sparks across many late-model 6-cylinder engines. Designed with a taper-cut nickel ground electrode and a precise pre-gap of 0.044" (1.1 mm), they suit fuel-injected and turbocharged applications where stable combustion, reduced misfires, and extended wear life matter. Each plug includes a crush washer and a non-removable nut electrical terminal for straightforward installation and dependable connection.

How do these plugs improve everyday driving?

Iridium’s fine-wire center electrode needs less voltage to produce a strong spark, which helps ignition happen more cleanly and consistently. That typically translates to crisper throttle response and smoother idle, especially in engines that operate under variable loads.

• Fine-wire iridium tip for consistent ignition and lower voltage demand.
• Copper core for efficient heat transfer and stable operating temperature.
• Pre-gapped to 0.044" for immediate fitment in compatible engines.
• Precision laser construction for predictable spark location and timing.

Are these plugs durable for long service intervals?

Yes — iridium tips combined with a corrosion-resistant nickel ground electrode and ceramic insulator extend usable life compared with standard copper plugs. They are engineered to maintain gap integrity and resist wear, lowering the need for frequent replacement in many driving conditions.

• Iridium tip resists erosion for longer service life.
• Resistor built in to reduce radio-frequency interference and protect electronics.
• Crush washer ensures a proper seal at each installation.
• Mid-projection design balances combustion chamber access and heat control.

Which vehicles and engine types fit this NGK part number?

The NGK LFR5AIX-11 (stock number 4469) fits a range of 6-cylinder engines across several makes when a 14 mm thread and 26.5 mm reach are specified. Common compatible applications include select Hyundai, Infiniti, Kia, Nissan, Suzuki, and Toyota 3.5L or 4.0L V6/6-cylinder engines from model years listed by manufacturers.

• Thread diameter: 14.0 mm; reach: 26.5 mm (1.043" reach).
• Heat range: NGK manufacturer rating 5 for moderate operating temperatures.
• Seat type: flat with crush washer included for correct gasket seating.
• Hex size: 5/8" (16 mm) for standard socket use during install.

What should I know about installation and maintenance?

These plugs come pre-gapped to 0.044" but always verify gap and torque to vehicle manufacturer specifications before final installation. Use the recommended torque and a clean thread surface; replace plugs in the full set to preserve ignition balance and engine smoothness.

• Verify pre-gap 0.044" and adjust only if OEM specs differ.
• Torque to vehicle-specific values to avoid thread or sealing damage.
• Replace all plugs at once for even engine performance.
• Inspect ignition coils and boots while servicing for leaks or wear.

Who is this for: Drivers and technicians seeking a durable, OEM-compatible performance spark plug for late-model 6-cylinder Hyundai, Infiniti, Kia, Nissan, Suzuki, and Toyota engines. Choose the NGK 4469 Iridium IX LFR5AIX-11 6-pack when you want a long-life iridium center electrode, precise construction, and straightforward fitment for models that call for a 14 mm thread, 26.5 mm reach, and a 0.044" gap.