A-NAFTULY Iridium Spark Plugs 8-Pack TR55IX 7164 for F-150 4.6L/5.4L — Direct-Fit, Long-Life

A-NAFTULY Iridium Spark Plugs 8 Pack (7164 / TR55IX) are a direct-fit replacement set designed to restore reliable ignition for V8 4.6L and 5.4L engines used in many Ford, GM and Cadillac models from the 1980s through 2010.

These eight iridium-tipped spark plugs are built to match OE reach, heat range, and gap for compatible V8 engines, offering consistent combustion without changing engine management. Sold as a full set, they replace worn originals that can cause rough idle, reduced fuel economy, or misfires. The kit’s fitment range spans popular trucks and sedans—most notably Ford F-150 years 1997–2010—plus many GM and Cadillac applications listed in the compatibility notes.

Will these spark plugs fit my vehicle and engine?

The A-NAFTULY TR55IX (7164) pack is intended for a wide group of V8 engines. It matches OE part references and is suitable where the engine requires the TR55 series reach and thread. Always verify the part reference and engine displacement before purchase.

• Direct reference numbers: 7164, TR55IX, 3403, TR55GP, 3951, TR55
• Common Ford fitment: F-150 (1997–2010), Expedition/Explorer (1997–2004), Mustang (1993–2004)
• Also fits many Cadillac, Chevrolet, GMC, Lincoln, Mercury applications—see full vehicle list

How do iridium tips affect ignition and longevity?

Iridium electrodes are harder and finer than conventional nickel, producing a more-focused spark and slower electrode wear. That typically means steadier spark performance over longer service intervals compared with standard plugs. Iridium’s durability helps maintain gap integrity under normal driving conditions.

• Fine center electrode improves ignition consistency
• Resists erosion to maintain gap and timing characteristics
• Designed for extended service intervals versus standard plugs

What should I expect during installation and maintenance?

These plugs are sold as a complete eight-piece set so you can replace all cylinders at once for balanced performance. They install like stock plugs—use correct torque, a clean thread, and the specified gap or pre-gapped condition if provided. Inspect boots, wires, or coil packs during service and replace any damaged ignition components to avoid repeat issues.

• Sold as a set of 8 for full V8 replacement
• Follow manufacturer torque specs and anti-seize recommendations
• Check ignition leads/coils while changing plugs for complete repair

What warranty and support come with the A-NAFTULY set?

A-NAFTULY provides a 12-month worry-free warranty covering defects and fitment issues originating from the product. Their customer support is available for fitment questions and replacement requests if you encounter a covered problem. Keep your purchase details and vehicle information ready when contacting support.

• 12-month warranty from A-NAFTULY on manufacturing issues
• Customer support for fitment assistance and claims
• Pack includes eight iridium spark plugs for immediate installation

Who is this for: Drivers and DIY mechanics who own V8-powered vehicles—especially Ford F-150 owners from model years 1997–2010—seeking a complete, direct-fit iridium plug set for improved ignition stability and longer service life. It’s also suited for fleet maintenance shops and technicians replacing all cylinders at once for balanced engine performance. Verify compatibility with your engine reference and year before ordering to ensure an exact match.