X4XZ UF550 Ignition Coil & 1406 Double Iridium Spark Plug Kit — 6-Cylinder 3.5L Nissan/Infiniti Fit, OE Replacement

X4XZ UF550 ignition coil pack paired with 1406 double iridium spark plugs is a complete six-cylinder replacement kit designed to restore reliable spark delivery and consistent combustion for compatible Infiniti and Nissan 3.5L engines.

This all-in-one kit combines six high-performance UF550 ignition coils and six 1406 double iridium spark plugs engineered to match or exceed OE fit and function (OE# 22448-JA10C / 5C1727). The components are built with durable materials — thermoplastic coil connectors, stainless-steel springs, ferrite noise suppression and double iridium electrodes — to deliver long service life, stable ignition, and simplified installation. It’s supplied as a direct-replacement set for many Infiniti and Nissan 3.5L models; always verify compatibility with your vehicle before purchase.

Which models and years will this kit fit?

This kit targets a broad range of Infiniti and Nissan vehicles powered by the 3.5L V6. Fitment covers many EX, FX, G, JX, M, Q and QX series Infinitis and 350Z, Altima, Maxima, Murano, Pathfinder and Quest Nissans across the listed model years. Confirm fit by comparing the part numbers (UF550 / 1406) or checking the second product image for visual match to your existing coils and plugs.

• Infiniti examples: 2008–2012 EX35, 2009–2012 FX35, 2014–2018 Q50, 2014–2019 QX60.
• Nissan examples: 2007–2009 350Z, 2007–2018 Altima, 2009–2019 Maxima and Murano.
• Replaces OE numbers: C1670, 22448-JA10C, 5C1727 — check these on your vehicle.

How do these coils and plugs improve engine performance?

The ignition coils and double iridium plugs are designed to provide a steady, high-voltage spark across a wide range of operating conditions. Better spark consistency helps reduce misfires, stabilizes idle, and supports more complete combustion which can improve drivability and throttle response when compared to worn OEM parts.

• Double iridium electrodes: longer life and consistent firing for up to 100,000 km.
• Ferrite noise suppressor and stainless-steel spring: reduce interference and ensure reliable contact.
• Thermoplastic coil connector: resists heat-related cracking and improves connection durability.

What should I expect during installation and maintenance?

The kit matches OE dimensions so installation is typically a direct swap using standard tools; no additional tuning is required. While the package does not include an instruction manual, basic mechanical experience or a mechanic’s help will get the job done quickly. Routine checks during regular service intervals will keep the system performing.

• Package contains six ignition coils and six double iridium spark plugs — enough for a full 6-cylinder replacement.
• Recommended: check torque specs for spark plugs and inspect wiring harness and boots for wear during installation.
• After-install: clear any diagnostic trouble codes and perform a short test drive to confirm smooth idle and no misfires.

Are there quality assurances and after-sales support?

X4XZ supplies these replacement parts with attention to materials and assembly to closely match OE performance. The brand provides one year of product service and 24-hour customer support for installation or quality concerns. Keep purchase details and vehicle information handy when contacting support.

• One-year product service and responsive customer support.
• Components built to reduce RFI and withstand thermal cycling.
• Designed as direct replacements to simplify diagnostics and repair.

Who is this for: This X4XZ UF550 + 1406 kit is intended for owners, DIY mechanics, and professional technicians who need a full six-cylinder ignition replacement for compatible Infiniti and Nissan 3.5L engines. Choose this kit if you’re experiencing misfires, rough idle, or declining spark performance and want a long-life, OE-style replacement set that covers coils and plugs in one purchase.