Ford Expedition 3.5L EcoBoost Spark Plug Guide (2015-2023)
Keep your Expedition's turbocharged engine running strong by choosing the right spark plugs.
- The 3.5L EcoBoost engine is sensitive; use only OEM Motorcraft or high-quality Iridium plugs from NGK or Denso.
- Change spark plugs more frequently than the owner's manual suggests, typically every 30,000 to 60,000 miles, to prevent performance issues.
- A flashing check engine light indicates a serious misfire that requires immediate attention to prevent damage to other components.
- Always verify the spark plug gap before installation, even if the plugs are advertised as 'pre-gapped'.
Understanding Spark Plugs in Your Expedition
The 3.5L EcoBoost engine in your 2015-2023 Ford Expedition is a high-performance, turbocharged powerhouse. Unlike older, simpler engines, it's very particular about its spark plugs. Using the correct type of plug, gapped properly, is not just a suggestion—it's essential for preventing issues like engine misfires, poor fuel economy, and even long-term damage. Worn or incorrect spark plugs can struggle to ignite the fuel and air mixture under the high pressure created by the turbos, leading to a rough-running engine.
Symptoms of Failing Spark Plugs
When your spark plugs are wearing out, your Expedition will give you several warning signs. Ignoring them can lead to more significant problems, like damage to your catalytic converter. Look out for a flashing check engine light, which signals a misfire that needs immediate attention.
- Rough Idle: The engine may shake or vibrate more than usual when you're stopped.
- Poor Acceleration: The vehicle may feel sluggish or hesitant when you press the gas pedal.
- Reduced Fuel Economy: Worn plugs can cause fuel efficiency to drop by up to 30%.
- Engine Misfires: You might feel a stutter or stumble from the engine, especially under load (like towing or accelerating hard). 🎬 See how to diagnose and fix that common EcoBoost stutter. This is often accompanied by a flashing check engine light.
- Difficulty Starting: While less common with modern ignitions, weak plugs can make the engine harder to start.
Known Issues & Recalls
As of early 2026, there are no specific recalls or widespread Technical Service Bulletins (TSBs) directly for spark plugs on the 2015-2023 Ford Expedition. However, misfire issues (often caused by worn plugs) are a common topic among owners. It's crucial to address misfire codes (like P0300-P0306) promptly to avoid other component failures. There was a recall for some 2024-2025 models for a misaligned engine cup plug that could cause an oil leak, but this is unrelated to the spark plugs themselves.
Choosing the Right Aftermarket Spark Plugs
For the 3.5L EcoBoost, not all spark plugs are created equal. While many aftermarket brands are available, owner and mechanic consensus strongly favors using either the OEM part or a high-quality equivalent.
OEM vs. Aftermarket
Ford's own Motorcraft plugs are the factory-installed part and are considered the benchmark for performance and reliability in this engine. Often, these Motorcraft plugs are manufactured by NGK or Denso, so choosing the equivalent Iridium plug from these brands is a safe bet. Cheaper, copper or single platinum plugs from budget brands are not recommended for the EcoBoost engine, as they wear out much faster and can cause performance issues. Many owners report problems when using brands other than Motorcraft or NGK.
Brand Quality Tiers for Your Expedition
- Tier 1: OEM & OEM-Equivalent: Motorcraft, NGK, and Denso. These brands are the top choice. Motorcraft is the official Ford part (OEM part numbers include SP-594, CYFS12YRT3). NGK and Denso are often the original manufacturers for Ford and their Iridium plugs offer excellent performance and longevity. Ford Performance also offers colder heat range plugs (M-12405-35T) for tuned or high-performance applications.
- Tier 2: Quality Aftermarket: Bosch and Champion offer Iridium plugs that can be a viable alternative. However, owner feedback is mixed compared to the Tier 1 brands. Some owners have tried Bosch plugs and switched back to Motorcraft due to performance differences.
- Tier 3: Budget Options: Brands like Accel and Autolite are generally considered budget-friendly. While they may offer compatible parts, they are not widely recommended by Expedition or F-150 3.5L EcoBoost owners due to the engine's sensitivity.
A Note on Spark Plug Gap
The "gap" is the space between the two electrodes at the tip of the spark plug. For the EcoBoost engine, this gap is critical. While most high-quality Iridium plugs come pre-gapped, it is essential to verify the gap with a feeler gauge before installation. 🎬 Watch this to avoid a common mistake when gapping plugs. An incorrect gap can lead to misfires and poor performance. The stock gap is typically around 0.031 inches, but always check the specific requirements for your vehicle and the plug manufacturer.
Cost of Spark Plug Replacement
The cost can vary based on who does the work and which parts you choose.
| Item | Estimated Cost |
|---|---|
| New Aftermarket Spark Plugs (Set of 6) | $65 - $150 |
| New OEM Motorcraft Spark Plugs (Set of 6) | $90 - $170 |
| Shop Labor | $272 - $399 |
| Total Professional Replacement | $374 - $501 |
Frequently Asked Questions
How often should I change the spark plugs on my Expedition?
While Ford's official interval can be up to 100,000 miles, most experts and owners recommend a much shorter interval for the 3.5L EcoBoost, typically between 30,000 and 60,000 miles. If you tow frequently, drive aggressively, or have a tuned engine, changing them closer to 30,000 miles is a good idea to maintain peak performance.
Is this a DIY job?
For a moderately experienced DIYer, yes. The job takes about 1-2 hours. 🎬 Watch this step-by-step guide to changing your Expedition's spark plugs. You will need a socket wrench with extensions, a 14mm spark plug socket, a torque wrench, and a spark plug gap tool. It's important to blow compressed air into the spark plug wells before removing the old plugs to prevent debris from falling into the engine cylinders.
What are Iridium spark plugs and why are they recommended?
Iridium is a very hard, precious metal that is excellent at conducting electricity and resisting wear. Iridium spark plugs last much longer and provide a more consistent, powerful spark than older copper or platinum plugs. For a high-compression, turbocharged engine like the EcoBoost, the durability and performance of Iridium plugs are essential.
Should I replace the ignition coils at the same time?
Not necessarily. Unlike spark plugs, which are a routine maintenance item, ignition coils (also called coil packs) are typically only replaced when they fail. A common diagnostic step for a misfire code on a specific cylinder is to swap that cylinder's coil with another one to see if the misfire follows the coil. If it does, you only need to replace the one faulty coil.
Helpful Videos
Technical Specifications
OEM Part Numbers: SP-594 CYFS12YRT3 SP-578 SP-542
The 2015-2023 Ford Expedition with the 3.5L EcoBoost V6 engine requires six Iridium-type spark plugs. A 14mm socket is typically needed for removal and installation.
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The information in this article is provided for general reference and educational purposes only. Vehicle specifications, procedures, and part compatibility can vary by production date, trim level, and region. Always consult your vehicle's factory service manual and verify part numbers before purchasing or performing repairs. Safety-critical components such as airbags, seat belts, and braking systems should be installed by a qualified professional.
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- 🎬 Helpful Videos
- 🛍️ Shop This Part
- Understanding Spark Plugs in Your Expedition
- Symptoms of Failing Spark Plugs
- Known Issues & Recalls
- Choosing the Right Aftermarket Spark Plugs
- OEM vs. Aftermarket
- Brand Quality Tiers for Your Expedition
- A Note on Spark Plug Gap
- Cost of Spark Plug Replacement
- Frequently Asked Questions
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