X4XZ ignition coil & spark plug kit 6-piece — direct-fit double‑iridium plugs for Nissan/Infiniti V6, restores reliable spark

X4XZ UF349 ignition coil set paired with 224018H515 double iridium spark plugs provides a direct-fit replacement kit for many Nissan, Infiniti and Suzuki V6 engines, restoring reliable spark and smoother running.

If your V6 is showing signs of misfire, low power or rough idle, replacing worn ignition coils and spark plugs often solves the issue. This X4XZ kit contains six coil packs and six double-iridium plugs engineered to meet or exceed original-equipment specifications. The components are built with durable materials and improved connections to withstand heat, reduce electrical noise and extend service life compared with conventional plugs.

Which vehicles is this ignition coil and spark plug kit compatible with?

The X4XZ UF349 + 224018H515 kit fits a wide range of Nissan, Infiniti and Suzuki V6 models from the early 2000s through the mid‑2010s. It covers many 3.5L and 4.0L V6 applications where the OE part numbers match.

• Nissan: Altima 3.5L (02–06), Frontier 4.0L (05–18), Maxima 3.5L (02–16), Murano 3.5L (03–15), Pathfinder 3.5L/4.0L (02–12), Quest 3.5L (04–09), XTERRA 4.0L (05–14), NV vans 4.0L (12–16).
• Infiniti: I35 3.5L (02–04), QX4 3.5L (02–03).
• Suzuki: Equator V6 4.0L (2009–2012).
• Confirm vehicle fitment against OE numbers shown on the product images before ordering.

How do these parts improve engine performance and drivability?

Fresh coils and double-iridium plugs restore consistent ignition timing and stronger sparks, which helps reduce misfires and can improve throttle response. The materials and connectors are chosen to resist heat and vibration for longer, steadier operation.

• Double-iridium electrodes provide stable, precise sparks with extended service life (longer intervals versus standard plugs).
• Thermoplastic coil connectors and stainless steel springs improve electrical transfer and resist heat-induced failures.
• Internal ferrite noise suppression reduces radio-frequency interference that can affect electronics.

What does the kit include and which OE numbers does it replace?

The kit supplies what you need to replace all six cylinder ignition components at once: six ignition coil packs and six double‑iridium spark plugs. It’s packaged as a complete set for easier maintenance and consistent part matching.

• Included: Ignition Coil Packs x6, Double Iridium Spark Plug x6 (no printed instruction manual).
• Common OE references: UF349, 224018H515 and replacement cross‑references like C1406, 50075, 22248-8J115, 22448-8J111 and others listed on the product images.
• Designed to match or improve on original design for straightforward installation by a trained technician or experienced DIYer.

How do I handle installation and after‑sales support?

Installation is typically a direct swap: disconnect battery, remove engine cover if present, unplug each coil, unseat the old plug, and install the new plug and coil. If you prefer, a professional installer will ensure correct torque and gap checks.

• Basic tools required include ratchet, spark plug socket, torque wrench and dielectric grease for boots if desired.
• X4XZ offers 24‑hour customer service and a 1‑year product support window for fitment or quality questions.
• If you encounter fit or performance issues, contact customer support before returning parts to verify application and troubleshooting steps.

Who is this for: This kit is intended for owners and technicians maintaining Nissan, Infiniti or Suzuki V6 vehicles that match the listed models and OE cross‑references. It is well suited for drivers noticing misfires, decreased power or rough idling who want a complete six‑cylinder ignition refresh with longer‑lasting iridium plugs and robust coil packs engineered to resist heat and electrical interference.