Marsram Ignition Coil & Spark Plug Kit for 5.4L V8 — FD508-Style 8-Coil with Iridium Plugs

Marsram's FD508 ignition coil and iridium spark plug kit replaces worn coils and plugs on 5.4L V8 Ford/Lincoln engines to restore reliable spark, smoother idling, and consistent starting.

This comprehensive aftermarket kit includes eight FD508-style ignition coils and eight high-performance iridium spark plugs designed for 5.4L V8 applications used across Ford F-150, Expedition, Navigator and select Super Duty models from the mid-2000s. Each coil uses durable epoxy and engineering-grade plastic on the exterior with high-conductivity copper windings inside. The spark plugs feature iridium center electrodes and corrosion-resistant materials to limit gap growth and sustain efficient combustion over time.

How will this kit improve my 5.4L V8's starting and idle behavior?

Replacing degraded coils and plugs often cures hard starts, rough idle, and misfires caused by weak or inconsistent spark. Fresh coils restore higher-voltage delivery to the plugs while iridium electrodes maintain a stable spark, helping the engine fire evenly across all cylinders.

• Includes 8 coils matched to FD508 appearance and electrical specs for V8 engines
• Iridium plugs resist electrode wear and reduce gap growth
• Improves ignition consistency for smoother idle and crisper starts

Will these parts fit my specific Ford or Lincoln model?

The kit is built for 5.4L V8 engines with black straight coil boots only; it is not compatible with V10 engines or coils that have brown or curved boots. Verify the coil look on your vehicle against the FD508-style coil image or consult fitment charts before ordering.

• Common fitment: 2005–2007 Ford F-150 5.4L V8 variants
• Also fits select 2004–2008 F-Series, 2005–2007 Expeditions and 2005–2007 Lincoln Navigators/Mark LT
• Replaces OEM numbers like DG511, FD508, 3L3Z-12029-BA, UF537 and related part numbers

What materials and construction should I expect from the coils and plugs?

The ignition coils use an epoxy-coated outer housing with high-strength engineering plastic to resist heat and deformation under engine bay conditions. Internally they feature high-conductivity copper windings for efficient energy transfer. The spark plugs use iridium center electrodes and corrosion-resistant designs to preserve gap integrity and stable spark formation over many miles.

• Coil shell: epoxy resin plus engineering plastic for heat resistance
• Internal coil conductor: high-conductivity copper for faster ignition
• Spark plug electrode: iridium for long life and stable spark gap

How does the kit package and what warranty covers it?

The kit ships with eight matched ignition coils and eight iridium spark plugs to replace a full-bank V8 set in one service. Marsram backs the kit with a one-year warranty and offers customer support for fitment or product concerns.

• Complete set: 8 coils + 8 spark plugs, ready for full V8 replacement
• 1-year limited warranty from Marsram with customer support
• Sold as an aftermarket direct-replacement kit — check fitment before installation

Who is this for: This kit is aimed at owners or technicians working on mid-2000s Ford and Lincoln vehicles powered by the 5.4L V8 who need a full ignition bank refresh. It suits drivers experiencing misfires, rough idle, slow starts or decreased throttle response, and those performing scheduled maintenance who want durable coils and long-life iridium plugs. Verify your engine is the 5.4L V8 and that your vehicle uses black straight-boot coils before purchasing.