autoexact Ignition Coil & Iridium Spark Plug Kit for Ford 4.6/5.4L — 8 Coils + 8 Pre‑gapped Plugs

Autoexact FD504 ignition coil pack and iridium spark plug kit is an OEM-fit replacement set (8 coils + 8 plugs) designed to restore ignition performance for Ford 4.6L and 5.4L engines.

If your V8 is showing misfires, rough idle, poor throttle response, or an illuminated check engine light tied to ignition faults, this kit provides a complete plug-and-coil refresh in one purchase. The set pairs epoxy-potted coil packs built to OEM dimensions with fine-wire iridium plugs pre-gapped for quick installation, offering improved spark consistency and long service life compared with worn components.

How will these coils and plugs affect engine performance?

Replacing degraded coils and spark plugs can restore lost power and smoother operation without engine modifications. The coil packs deliver steady high-voltage output while the iridium tips provide reliable ignition, helping reduce misfires and restore throttle feel.

• Stronger, more consistent spark improves combustion efficiency.
• Reduces rough idle, hesitation, and vibration linked to misfires.
• Helps resolve common P0300–P0308 diagnostic trouble codes.

Are these parts an easy do-it-yourself swap?

Yes — each coil and plug is engineered as a direct OEM replacement for compatible years and engines, so installation is typically plug-and-play with basic hand tools. Components come pre-greased and plugs are pre-gapped to the specified 1.3mm, streamlining the job for home mechanics.

• Includes 8 ignition coil packs and 8 pre-gapped iridium plugs for a full-bank service.
• Factory pre-lubricated with dielectric grease for proper seating and sealing.
• Recommended torque: 11.06 ft·lb (15 N·m) for correct installation.

What durability and compatibility can I expect?

Autoexact uses epoxy-potted coils for heat resistance and long-term sealing performance, while the fine-wire iridium plugs are rated for extended life under normal driving. The kit matches many OE and replacement part numbers and fits a broad list of Ford, Mercury, and Lincoln models with 4.6L or 5.4L V8s.

• Plugs typically last up to 40,000 miles under normal conditions.
• Coils tested for voltage output, insulation, and sealing.
• Compatible with many OEM numbers (FD504, DG508, F7TU12029BA, etc.) — verify fitment before purchase.

Will these plugs fit my vehicle’s heat range and thread specs?

The included iridium plugs are engineered to replace heat range 5 or 6 equivalents (e.g., TR55GP or ITR6F13) that share identical physical specifications. They use a 14mm thread, tapered seat, and a 1.3mm preset gap, so they swap directly with the original equipment on applicable engines.

• 14mm thread and tapered seat match OEM dimensions.
• 1.3mm preset gap for correct spark timing without adjustment.
• 100% interchangeable between the two compatible heat ranges.

Who this kit is for: drivers, fleet owners, and DIY mechanics who need a full ignition refresh for Ford 4.6L or 5.4L engines will benefit most. If your vehicle shows ignition-related drivability issues or you’re performing scheduled maintenance, this complete 8-coil/8-plug set saves time and ensures matched components. Always confirm year, make, model, and engine before ordering to ensure proper fitment. The kit is backed by a 2-year warranty and lifetime technical support for installation assistance and peace of mind.