{"product_id":"woofixing-iridium-spark-plugs-for-ford-5-4l-v8-8-pack-sp515-sp546-oe-fit-long-life","title":"WOOFIXING Iridium Spark Plugs for Ford 5.4L V8 — 8-Pack SP515\/SP546, OE-Fit \u0026 Long-Life","description":"\u003cp\u003e\u003cstrong\u003eWOOFIXING SP515 \/ SP546 iridium spark plugs are a direct-fit eight-piece replacement engineered to restore consistent ignition for Ford 5.4L and compatible 4.6L V8 engines.\u003c\/strong\u003e\u003c\/p\u003e\n\n\u003cp\u003eThese spark plugs are manufactured to match OE specifications for late-model Ford\/Lincoln\/Mercury V8 engines, providing a plug-and-play option for 2004–2008 F-150, F-250, F-350 (including Super Duty), Expedition, Mustang, and various Lincoln\/Mercury models. Each set contains eight iridium-tipped plugs designed to deliver steady high-voltage transfer, long electrode life, and improved throttle response when installed correctly. SP515 and SP546 share compatibility across many vehicles; SP515 tends to suit older engine variants while SP546 aligns with more recent factory requirements. Check your vehicle’s manual or part lookup to confirm the correct code before ordering.\u003c\/p\u003e\n\n\u003ch3\u003eHow do these plugs affect everyday driving performance?\u003c\/h3\u003e\n\u003cp\u003eReplacing worn plugs with these iridium units helps return smooth idling and consistent acceleration by ensuring reliable combustion across all cylinders. The iridium tip maintains spark integrity longer than standard electrodes, which supports more even firing and helps prevent misfires under load.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eEight plugs per package for complete V8 tune-ups.\u003c\/li\u003e\n  \u003cli\u003eIridium electrode for longer service life and consistent spark.\u003c\/li\u003e\n  \u003cli\u003eEngineered to meet factory gap and heat-range expectations.\u003c\/li\u003e\n  \u003cli\u003eHelps improve throttle response and reduce rough idle when worn plugs were the issue.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eAre these spark plugs compatible with my Ford or Lincoln model?\u003c\/h3\u003e\n\u003cp\u003eThese plugs are designed for a range of Ford\/Lincoln\/Mercury V8 applications, especially 5.4L and many 4.6L engines from model years roughly 2004–2008. Compatibility includes F-150, Expedition, Mustang, F-250\/F-350 Super Duty, Lincoln Navigator, and Mercury Mountaineer within the specified years, but you should verify part numbers or VIN-fitment just to be certain.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eCommon OE references: SP515, SP-515, SP546, SP-546, SP507, PZH14F, PZT2F.\u003c\/li\u003e\n  \u003cli\u003eAlso cross-referenced to codes like SP546X and several factory aftermarket catalog numbers.\u003c\/li\u003e\n  \u003cli\u003eSP515 favored for older engine assemblies; SP546 used more by newer factory specifications.\u003c\/li\u003e\n  \u003cli\u003eIdeal for complete V8 replacements—eight plugs included per set.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eWhat installation steps and torque settings should I follow?\u003c\/h3\u003e\n\u003cp\u003eProper installation prevents leaks and ensures a solid electrical connection. Use a torque wrench and tighten to the manufacturer-recommended setting to avoid damaging the threads or ignition components.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eRecommended torque: 25–30 N·m (2.5–3.0 kgf·m).\u003c\/li\u003e\n  \u003cli\u003eUse anti-seize only if specified by your shop manual; many iridium plugs come pre-coated.\u003c\/li\u003e\n  \u003cli\u003eReplace eight plugs for V8 engines to maintain balanced performance.\u003c\/li\u003e\n  \u003cli\u003eInspect coil boots and ignition wiring while plugs are out; replace if cracked or worn.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eWhat quality checks and warranty considerations apply?\u003c\/h3\u003e\n\u003cp\u003eEach spark plug receives rigorous quality control testing to ensure consistent high-voltage output and electrode integrity. WOOFIXING emphasizes stable ignition performance and longer service life through material selection and testing protocols.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eIridium tips tested for durability and consistent gap retention.\u003c\/li\u003e\n  \u003cli\u003eHigh-voltage conduction checked to reduce misfire risk.\u003c\/li\u003e\n  \u003cli\u003ePackaged as a complete eight-plug set for V8 engines to simplify maintenance.\u003c\/li\u003e\n  \u003cli\u003eFollow product listing or retailer terms for warranty details and returns.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cp\u003eWho is this for: This eight-pack is ideal for DIY mechanics and service shops replacing all spark plugs on Ford 5.4L or compatible 4.6L V8 engines from the mid-2000s range. If you drive an F-150, F-250, F-350 Super Duty, Expedition, Mustang, Lincoln Navigator, or Mercury Mountaineer from roughly 2004–2008 and want a long-lasting iridium replacement that meets OE cross-references (SP515\/SP546), these plugs offer a practical maintenance upgrade. Always confirm the correct SP code for your engine variant before purchase and use a torque wrench to ensure a proper, long-lasting installation.\u003c\/p\u003e\n\u003csection class=\"product-faq-snippet\"\u003e\u003ch3\u003eFAQ\u003c\/h3\u003e\n\u003cdiv class=\"faq-item\"\u003e\n\u003cp class=\"faq-q\"\u003eQ: Do SP515 and SP546 fit the same Ford engines?\u003c\/p\u003e\n\u003cp class=\"faq-a\"\u003eA: Yes—SP515 and SP546 are compatible across many of the same Ford V8 models; SP515 often suits older assemblies while SP546 matches newer factory specs. Verify fit with your VIN or parts lookup.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"faq-item\"\u003e\n\u003cp class=\"faq-q\"\u003eQ: What torque should I use when installing these plugs?\u003c\/p\u003e\n\u003cp class=\"faq-a\"\u003eA: Use a torque wrench and tighten to 25–30 N·m (2.5–3.0 kgf·m) for a secure seal and reliable electrical contact.\u003c\/p\u003e\n\u003c\/div\u003e\u003c\/section\u003e","brand":"WOOFIXING","offers":[{"title":"Default Title","offer_id":67587433398457,"sku":"B0FP94JXHW","price":99.48,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0822\/3765\/3177\/files\/woofixing-front-packaging-sp515-sp546.jpg?v=1790507792","url":"https:\/\/redleafauto.ca\/products\/woofixing-iridium-spark-plugs-for-ford-5-4l-v8-8-pack-sp515-sp546-oe-fit-long-life","provider":"Redleaf Auto","version":"1.0","type":"link"}