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The KF-151 Iridium Spark Plug is the 2026-ready replacement for the Ford modular V8 and EcoBoost ecosystem. It directly cross-references Motorcraft SP-509, SP-515 and SP-534 plus NGK 6509/5464 applications across the 2010–2020 F-150 and the Super Duty 6.2L Boss V8.

The 0.6mm iridium-rhodium fine-wire center electrode delivers consistent ignition energy under high-load turbo conditions, and trivalent chromium plating on the shell counters corrosion in heavy-duty fleet environments. Certification backs it up: SAE J548 electrical performance curves, ISO 9001:2015 manufacturing traceability and 2026 IATF 16949 quality benchmarks.

Engines Covered, 2010–2020

One part number, four platforms — match your engine before ordering:

• 5.4L Triton 3V (F-150): Motorcraft SP-509 / SP-515
• 3.5L EcoBoost (F-150): Motorcraft SP-528 / SP-534
• 5.0L Coyote (F-150): Motorcraft SP-519 / SP-589
• 6.2L Boss V8 (Super Duty): Motorcraft SP-509 equivalent, dual-plug heads

Full Spec Chart

Every value below comes straight from the KF-151 application data. Use your engine's column for gaps, heat range and service life.

Electrode and Insulator Design

Laser-Welded Fine-Wire Center

The center electrode is a laser-welded 0.6mm iridium-rhodium alloy (Ir-90/Rh-10) paired with a platinum ground pad. That combination holds the spark steady under high-load turbo conditions.

Insulator and Voltage Headroom

The 95% alumina ceramic insulator provides >35kV/mm dielectric isolation and supports coil-on-plug output up to 40kV on 3.5L EcoBoost platforms — headroom for a boosted cylinder at full coil demand.

Shell, Plating and Resistance

The nickel-alloy shell carries trivalent chromium plating to prevent seizing in 2010–2020 F-150 cylinder heads. OE-spec 5kΩ resistance prevents RFI interference with CAN-FD networks — that is what makes the plug compatible with 2026 CAN-bus and OBD-II diagnostics.

Torque, Gaps and the Anti-Seize Rule

Torque every plug to 12–15 ft-lb (16–20 N·m) on dry threads. Per 2026 OEM guidance there is no anti-seize: Motorcraft guidance says anti-seize changes clamp load by roughly 20%, and the trivalent chromium plating already prevents seizure.

Pre-set gaps by engine:

• 5.4L Triton 3V: 0.044 in (1.1mm)
• 3.5L EcoBoost: 0.030 in (0.76mm) — 0.028–0.031 in on tuned engines under boost
• 5.0L Coyote: 0.051 in (1.3mm)
• 6.2L Boss V8: 0.044 in (1.1mm)

Do not regap. Fine-wire iridium-rhodium electrodes are brittle and can crack if bent. Run the pre-set gap and verify with a wire-style gap tool if needed.

DTC Codes a Worn Plug Throws

Weak spark shows up fast in 2026 OBD-II monitors. When persistent misfire traces back to electrode gap fatigue, ceramic breakdown or RFI from off-spec resistance, this plug addresses:

• P0300–P0308 — random or cylinder-specific misfire
• P0316 — startup misfire
• P0350–P0358 — ignition coil circuits
• P0171/P0174 — lean exhaust from unstable idle spark
• P0420 — catalyst efficiency loss from incomplete combustion

If a code survives new plugs, good coil boots and 12–15 ft-lb of torque, the fault sits elsewhere in the ignition system.

Engine-Specific Installation Notes

5.4L Triton 3V

2010+ 5.4L 3V engines use one-piece plugs, which eliminates the old two-piece break-off problem. The KF-151 has a one-piece shell with anti-seize-free dry-thread specs. If P0308 persists after replacement, check the ignition coil boots and torque to 15 ft-lb.

6.2L Boss V8

The Boss V8 runs two plugs per cylinder — 8 intake-side and 8 exhaust-side, 16 total. Use the same part number in all 16 positions; this plug covers both locations. Two-valve SOHC heads take heat range 8.

3.5L EcoBoost

On a P0300 under boost, check gap erosion first. The 0.6mm iridium tip resists blowout at 20+ psi, which is what supports the 60,000-mile interval on forced-induction engines.

All four engines share the same thread spec: M14 x 1.25, 25mm reach, tapered seat — a direct fit for every listed coil-on-plug system.

More Ignition Parts for Your Fleet

Koeep covers more than one truck generation. Still running a 1996–1999 F-150 or F-250 alongside your newer Super Duty? The Spark Plug Wire Set Compatible with 1996-1999 Ford Lincoln Mercury F-150 F250 is built for those engines, and the Spark Plug Wire Set compatible with Ford 1996-1999 Crown Victoria F-250 F-150 covers Crown Victoria and F-250/F-150 bodies from the same model years.

Smaller Ford engines are covered too: the 4 Pack Spark Plugs Super Iridium 96621 For 2012-2013 Ford Explorer 2.0L L4 Jagua serves the 2012–2013 Explorer 2.0L L4. For everything ignition-related in one place — plugs, wire sets, coils — browse the Ignition Systems & Components collection.

If some of the budget goes to the cabin instead of the engine bay, the Koeep guide on how to transform a Ford Fusion interior with a 5D carbon fiber center console sticker is a quick read.

2026 Verification and Compliance Checklist

1. Material standard: SAE J548 insulator compliance, ≥95% alumina ceramic, IATF 16949 traceability, RoHS 3 / EU 2026 materials restriction compliance.
2. DTC mapping: P0300–P0308, P0316, P0350–P0358, P0171/P0174 and P0420 are addressed when persistent misfire stems from electrode gap fatigue, ceramic breakdown or RFI from off-spec resistance.
3. SKU lifecycle: the KF-151 aligns with Motorcraft SP-509/SP-515/SP-534 equivalency and is planned to remain in production through 2030 for 2010–2020 Ford platforms, with 100,000-mile durability on naturally aspirated engines.

Fleet buyers and bulk orders: send the request-for-quote form for volume pricing, or reach the team at support@koeep.com or on WhatsApp with fitment questions.

Frequently Asked Questions