X4XZ Ignition Coil Pack & Double Iridium Spark Plug Kit — 4-Pack for Kia/Hyundai, Direct-Fit Long-Life

The X4XZ UF651 ignition coil pack paired with NGK 9723 double iridium spark plugs is a direct-fit replacement kit designed to restore reliable spark delivery and consistent combustion for compatible Kia and Hyundai 4-cylinder models.

This complete 4-pack contains four ignition coil packs and four long-life double iridium spark plugs engineered to match or exceed OE specifications for fit and function. The components are built to resist heat and electrical noise while delivering stable spark energy, aiming to reduce misfires, improve throttle response, and help return fuel economy to expected levels when worn units are replaced. Confirm vehicle compatibility against the provided application list and the second product image before purchase.

Which vehicles does this kit fit?

This kit is manufactured to fit many Hyundai and Kia 4-cylinder engines from model years roughly 2011–2021. Fitment varies by model and production year, so visual verification of connector style is recommended.

• Hyundai: Elantra (2011–2016 GLS/Limited/SE 1.8L), Elantra GT (2014–2020 2.0L), Tucson (2014–2021 2.0L).
• Kia: Forte (2014–2016 1.8L/2.0L, Forte Koup 2.0L), Forte5 (2014–2018 2.0L), Soul (2012–2019 2.0L).
• Check for 2-pin vs. 4-pin coil connectors in 2017–2018 models before ordering.

How do these ignition coils and spark plugs improve engine performance?

The ignition coils and double iridium spark plugs in this kit restore efficient ignition timing and energy transfer, which helps reduce misfires and rough idling. Consistent spark reduces incomplete combustion and can lead to steadier throttle response and more predictable acceleration.

• Double iridium tips maintain a stable spark and longer service life—rated up to approximately 100,000 km under typical conditions.
• Coil design includes ferrite noise suppression to limit radio interference and ensure reliable signal delivery.
• Thermoplastic coil connectors resist thermal cycling and reduce fracture risk during repeated heating and cooling.

What are the build and quality features to expect?

Each coil and spark plug is constructed with materials chosen to withstand engine heat and electrical stress. The coils use stainless-steel springs and internal suppressors; the plugs feature dual iridium electrodes for longevity and stable gap performance.

• OE-referenced part numbers: UF651 coil compatible with NGK 9723 spark plug.
• Premium materials designed to resist corrosion, wear, and thermal degradation.
• Engineered for straightforward installation—direct-fit replacement with no modification required.

How easy is installation and what’s included in the box?

Installation is intended to be straightforward for a technician or mechanically inclined DIYer. The set is supplied with four ignition coils and four double iridium spark plugs—no printed manual included, but many users follow factory service procedures or online tutorials.

• Included: 4 x ignition coil packs, 4 x NGK 9723 double iridium spark plugs.
• Not included: instruction manual—use factory torque specs and gap checks during installation.
• After-sales support: 24-hour customer service and a 1-year product service warranty from X4XZ.

Who this is for: This replacement kit is intended for owners and technicians servicing compatible Hyundai and Kia compact vehicles that are experiencing ignition-related issues such as misfires, rough idle, or decreased fuel economy. Choose this kit if you want a direct-fit, longer-life spark plug option (double iridium) paired with coils designed to minimize interference and withstand repeated thermal cycles. Confirm connector type and part fitment for your specific model year before ordering to ensure compatibility.