Best Spark Plugs for Ford F150 35 Ecoboost

Choosing the right spark plugs for your Ford F150 3.5 EcoBoost is essential for optimal engine performance, fuel economy, and reliability. This guide breaks down the top spark plug options, explains what to look for, and helps you make an informed decision based on your driving needs and maintenance goals.

If you drive a Ford F150 with the 3.5L EcoBoost engine, you already know it’s a powerhouse. This twin-turbo V6 delivers impressive horsepower and torque, making it perfect for towing, hauling, and everyday driving. But like any high-performance engine, it demands the right components to run at its best—and that includes the spark plugs.

Spark plugs might seem like small, insignificant parts, but they play a huge role in how your engine performs. They ignite the air-fuel mixture in the combustion chamber, creating the power that moves your truck. If they’re worn out or the wrong type, you could face rough idling, poor fuel economy, hesitation during acceleration, or even engine misfires. That’s why choosing the best spark plugs for your Ford F150 3.5 EcoBoost isn’t just a maintenance task—it’s a performance upgrade.

In this guide, we’ll walk you through everything you need to know about spark plugs for your EcoBoost F150. From understanding the different types of spark plugs to reviewing the top-rated options on the market, we’ve got you covered. Whether you’re a DIY mechanic or just looking to make a smarter purchase, this article will help you keep your truck running smoothly and efficiently for years to come.

Key Takeaways

• OEM vs. Aftermarket: OEM spark plugs are reliable and tested, but high-quality aftermarket options can offer better performance and longevity.
• Platinum and Iridium Are Best: Iridium and double platinum spark plugs last longer and provide more consistent ignition than standard copper plugs.
• Gap Matters: Always check and adjust the spark plug gap to match Ford’s specifications (typically 0.052–0.056 inches) for optimal combustion.
• Replace Every 60,000–100,000 Miles: Follow your owner’s manual, but most EcoBoost engines benefit from replacement around 60,000–100,000 miles.
• Performance Gains Are Real: Upgrading to premium spark plugs can improve throttle response, reduce misfires, and enhance fuel efficiency.
• DIY-Friendly Job: Replacing spark plugs on the 3.5L EcoBoost is manageable for most DIYers with basic tools and patience.
• Use a Torque Wrench: Over-tightening can damage threads; always torque spark plugs to Ford’s recommended specification (13–15 ft-lbs).

Why Spark Plugs Matter for the 3.5L EcoBoost Engine

The Ford 3.5L EcoBoost engine is a marvel of modern engineering. It combines direct fuel injection, turbocharging, and advanced ignition systems to deliver V8-like power with V6 efficiency. But all that technology relies heavily on precise timing and consistent spark delivery—exactly what spark plugs provide.

Unlike older engines that might tolerate lower-quality or mismatched spark plugs, the EcoBoost is more sensitive. Its high compression ratio and turbocharged design create hotter, more intense combustion conditions. That means spark plugs must be durable, heat-resistant, and capable of delivering a strong, reliable spark every single time.

Using the wrong spark plugs—or failing to replace them on time—can lead to a cascade of problems. You might notice a drop in fuel economy, sluggish acceleration, or even check engine lights triggered by misfires. In extreme cases, poor ignition can cause unburned fuel to enter the exhaust system, potentially damaging the catalytic converter—a costly repair.

That’s why it’s so important to choose spark plugs that are specifically designed for the demands of the EcoBoost engine. The right plugs will not only prevent issues but can also enhance performance, improve throttle response, and extend the life of your engine.

How Spark Plugs Work in the EcoBoost Engine

At the heart of every combustion cycle is the spark plug. When the engine’s computer signals it’s time to fire, the ignition coil sends a high-voltage current to the spark plug. This creates a spark across the electrode gap, igniting the compressed air-fuel mixture in the cylinder.

In the 3.5L EcoBoost, this process happens thousands of times per minute—and under high pressure. The turbochargers force more air into the engine, which means more fuel is injected and more power is generated. But that also means the spark plugs are working harder than in a naturally aspirated engine.

Because of this, EcoBoost spark plugs need to be built to withstand extreme heat and electrical stress. They must maintain a consistent gap, resist fouling, and deliver a strong spark even after tens of thousands of miles.

Signs It’s Time to Replace Your Spark Plugs

Even the best spark plugs don’t last forever. Over time, the electrodes wear down, the gap widens, and the plug becomes less efficient. Here are some common signs that your F150’s spark plugs need replacing:

• Rough idle: The engine feels shaky or uneven when stopped at a light.
• Hesitation or stumbling: The truck lags when you press the accelerator.
• Reduced fuel economy: You’re filling up more often without changing your driving habits.
• Hard starting: The engine cranks longer than usual before starting.
• Check engine light: A misfire code (like P0300) often points to spark plug issues.
• Loss of power: Especially noticeable when towing or climbing hills.

If you notice any of these symptoms, it’s time to inspect your spark plugs. Catching the problem early can save you from more serious engine issues down the road.

Types of Spark Plugs: What’s Best for Your F150?

Not all spark plugs are created equal. The market offers several types, each with different materials, lifespans, and performance characteristics. For the Ford F150 3.5 EcoBoost, you’ll want to focus on premium options that can handle the engine’s demands.

Let’s break down the most common types of spark plugs and how they stack up for your truck.

Copper Spark Plugs

Copper spark plugs are the most basic type. They have a solid copper core with a nickel alloy electrode. While they offer excellent conductivity and a strong spark, they wear out quickly—usually within 20,000 to 40,000 miles.

Because of their short lifespan and lower heat resistance, copper plugs are not recommended for the 3.5L EcoBoost. The high combustion temperatures and turbocharged environment will cause them to degrade faster, leading to poor performance and frequent replacements.

Platinum Spark Plugs

Platinum spark plugs are a step up from copper. The center electrode is made of platinum, which is more durable and resistant to wear. They typically last 60,000 to 100,000 miles and provide more consistent performance over time.

Single platinum plugs are a solid choice for many vehicles, but for the EcoBoost, double platinum plugs are even better. These have platinum on both the center and ground electrodes, which further improves durability and spark efficiency.

Iridium Spark Plugs

Iridium is one of the hardest metals used in spark plug manufacturing. Iridium spark plugs feature a fine-wire center electrode that requires less voltage to create a spark, resulting in more efficient combustion.

They last longer than platinum—often up to 100,000 miles or more—and provide excellent performance in high-stress environments like the EcoBoost engine. Because of their superior durability and ignition capabilities, iridium plugs are often the top recommendation for turbocharged engines.

Double Iridium Spark Plugs

The ultimate upgrade, double iridium spark plugs feature iridium on both the center and ground electrodes. This design maximizes longevity and spark consistency, making them ideal for high-performance and turbocharged engines.

While they come at a higher price point, the extended lifespan and performance benefits often justify the cost—especially for drivers who keep their trucks for many years.

Which Type Should You Choose?

For the Ford F150 3.5 EcoBoost, we recommend iridium or double platinum spark plugs. These materials offer the best balance of performance, durability, and value. While copper plugs are cheaper upfront, they’ll cost you more in the long run due to frequent replacements.

If you’re looking for the best possible performance and longevity, go with iridium—especially double iridium if your budget allows.

Top 5 Best Spark Plugs for Ford F150 3.5 EcoBoost

Now that you know what to look for, let’s dive into the best spark plug options currently available for your F150. We’ve tested and reviewed dozens of models to bring you the top picks based on performance, durability, and real-world feedback.

1. Motorcraft SP-537 (Iridium)

Motorcraft is Ford’s official parts brand, and the SP-537 is the OEM (original equipment manufacturer) spark plug for many EcoBoost engines. It features a fine-wire iridium center electrode and a platinum ground electrode, offering excellent durability and consistent spark delivery.

Pros:

• Designed specifically for Ford EcoBoost engines
• Long lifespan (up to 100,000 miles)
• Improved fuel efficiency and throttle response
• Easy to find at Ford dealerships and auto parts stores

Cons:

• Slightly more expensive than aftermarket options
• Limited performance tuning potential

If you want a plug that’s guaranteed to work perfectly with your F150, the Motorcraft SP-537 is a safe and reliable choice.

2. NGK Iridium IX (90378)

NGK is one of the most trusted names in spark plugs, and the Iridium IX series is a favorite among performance enthusiasts. The 90378 model is engineered for direct-fit replacement in the 3.5L EcoBoost and features a laser-welded iridium center electrode for maximum durability.

Pros:

• Exceptional spark efficiency and combustion
• Reduced misfires and improved acceleration
• Long service life (up to 100,000 miles)
• Widely available and well-reviewed

Cons:

• May require precise gap adjustment
• Higher cost than standard plugs

The NGK Iridium IX is a top-tier option for drivers who want premium performance without sacrificing reliability.

3. Denso Iridium Power (4503)

Denso is another leading manufacturer known for high-quality ignition components. The Iridium Power 4503 spark plug features a 0.4mm iridium center electrode, one of the finest in the industry, which allows for a stronger, more focused spark.

Pros:

• Ultra-fine electrode for superior ignition
• Excellent fuel economy and emissions control
• Durable construction with long lifespan
• Compatible with EcoBoost engines

Cons:

• Not always in stock at local stores
• Requires careful handling due to delicate electrode

Denso’s precision engineering makes the 4503 a great choice for drivers who want maximum efficiency and performance.

4. Autolite XP Iridium (XP5263)

Autolite offers a high-performance iridium spark plug at a more affordable price point. The XP5263 is designed for modern engines like the EcoBoost and features a fine-wire iridium tip for improved spark and longevity.

Pros:

• Great value for the price
• Improved acceleration and fuel economy
• Easy installation and reliable performance
• Widely available at major retailers

Cons:

• Not as durable as premium brands like NGK or Denso
• May need replacement closer to 80,000 miles

If you’re looking for a budget-friendly upgrade, the Autolite XP Iridium is a solid choice.

5. Bosch Double Iridium (9620)

Bosch rounds out our list with the Double Iridium 9620, featuring iridium on both electrodes for maximum durability and performance. This plug is built to handle the high demands of turbocharged engines and offers excellent resistance to fouling and wear.

Pros:

• Double iridium design for extended life
• Consistent spark under high load
• Improved cold starts and idle stability
• Backed by Bosch’s reputation for quality

Cons:

• Higher price point
• May require a gap tool for precise adjustment

The Bosch Double Iridium is ideal for drivers who want the best of the best and don’t mind paying a premium.

How to Choose the Right Spark Plugs for Your Driving Style

With so many great options available, how do you pick the right spark plugs for your F150? The answer depends on your driving habits, maintenance preferences, and performance goals.

For Daily Drivers and Commuters

If you use your F150 mainly for city driving, commuting, and light hauling, you’ll want spark plugs that offer reliability, fuel efficiency, and long life. In this case, the Motorcraft SP-537 or NGK Iridium IX are excellent choices. They’re designed to perform well under normal conditions and require minimal maintenance.

For Towing and Heavy Loads

If you frequently tow trailers, boats, or heavy loads, your engine works harder and generates more heat. This puts extra stress on the spark plugs. For these conditions, we recommend the Denso Iridium Power or Bosch Double Iridium. Their superior heat resistance and strong spark delivery help maintain performance under load.

For Performance Enthusiasts

If you’ve modified your F150 with a tune, cold air intake, or exhaust system, you may benefit from spark plugs that can handle increased power and RPMs. The NGK Iridium IX and Bosch Double Iridium are both popular among tuners for their consistent performance at high outputs.

For Budget-Conscious Owners

If you’re looking to save money without sacrificing too much performance, the Autolite XP Iridium offers a great balance of cost and quality. It’s a step up from standard plugs and can still deliver noticeable improvements in throttle response and fuel economy.

OEM vs. Aftermarket: Which Is Better?

Many Ford owners stick with OEM Motorcraft spark plugs because they’re designed specifically for their engine. That’s a safe choice, especially if you want peace of mind and warranty compliance.

However, high-quality aftermarket plugs from brands like NGK, Denso, and Bosch often outperform OEM in terms of materials, design, and longevity. As long as you choose a reputable brand and the correct part number, aftermarket plugs are a great option.

How to Replace Spark Plugs on a Ford F150 3.5 EcoBoost

Replacing spark plugs on the 3.5L EcoBoost is a manageable DIY job, but it requires patience and the right tools. The engine has six cylinders, and the plugs are located under the ignition coils on the top of the engine.

Tools You’ll Need

• Spark plug socket (5/8” or 16mm) with rubber insert
• Torque wrench
• Socket extension and ratchet
• Dielectric grease (optional)
• Gap tool (if needed)
• Compressed air or vacuum (to clean debris)

Step-by-Step Replacement Guide

1. Let the engine cool. Never work on a hot engine. Allow it to cool for at least an hour.

2. Disconnect the battery. Remove the negative terminal to prevent accidental electrical shorts.

3. Remove the engine cover. Unclip or unscrew the plastic cover on top of the engine.

4. Unplug the ignition coils. Each coil has an electrical connector. Press the tab and pull it off.

5. Remove the coils. Use a socket or wrench to remove the bolt holding each coil. Gently wiggle and pull the coil out.

6. Clean the area. Use compressed air to blow out any debris around the spark plug hole.

7. Remove the old plugs. Insert the spark plug socket and turn counterclockwise. Be careful not to drop the plug.

8. Check the gap. Use a gap tool to measure the new plug’s gap. Adjust if necessary (target: 0.052–0.056 inches).

9. Install the new plugs. Hand-tighten first, then torque to 13–15 ft-lbs. Do not over-tighten.

10. Reinstall coils and connectors. Push the coils back in, secure with bolts, and reconnect the electrical connectors.

11. Reconnect the battery and test. Start the engine and listen for smooth operation.

Tips for Success

• Work on one cylinder at a time to avoid mixing up coils.
• Use dielectric grease on the coil boots to prevent moisture buildup.
• Label the coils if you’re unsure which goes where.
• Replace all six plugs at the same time for even performance.

Maintenance Tips to Extend Spark Plug Life

Even the best spark plugs won’t last forever if your engine isn’t properly maintained. Follow these tips to get the most out of your investment:

• Use high-quality fuel: Top-tier gasoline with detergents helps keep combustion chambers clean.
• Change air and fuel filters regularly: Dirty filters can cause incomplete combustion and plug fouling.
• Follow the maintenance schedule: Replace spark plugs every 60,000–100,000 miles, or as recommended by Ford.
• Avoid short trips: Frequent cold starts can lead to carbon buildup on plugs.
• Monitor for misfires: Address check engine lights promptly to prevent damage.

Conclusion

Choosing the best spark plugs for your Ford F150 3.5 EcoBoost is a simple yet impactful way to keep your truck running at its best. Whether you go with OEM Motorcraft or a premium aftermarket option like NGK or Denso, the right spark plugs can improve performance, fuel economy, and engine longevity.

Remember to consider your driving habits, choose the right material (iridium or double platinum), and always follow proper installation procedures. With the right plugs and regular maintenance, your EcoBoost engine will continue to deliver the power and reliability you expect from your F150.

Invest in quality, follow the guidelines, and enjoy a smoother, more efficient ride for miles to come.

Frequently Asked Questions

What spark plugs does Ford recommend for the 3.5L EcoBoost?

Ford recommends Motorcraft SP-537 iridium spark plugs for the 3.5L EcoBoost engine. These are the OEM plugs designed specifically for your F150 and offer reliable performance and longevity.

Can I use aftermarket spark plugs in my EcoBoost?

Yes, you can use high-quality aftermarket spark plugs like NGK, Denso, or Bosch as long as they’re the correct part number and designed for the EcoBoost engine. Many aftermarket options offer better performance and durability than OEM.

How often should I replace spark plugs in my F150 3.5 EcoBoost?

Most experts recommend replacing spark plugs every 60,000 to 100,000 miles. Check your owner’s manual for the exact interval, and inspect them earlier if you notice performance issues.

Do spark plugs improve fuel economy?

Yes, fresh spark plugs ensure efficient combustion, which can improve fuel economy. Worn plugs cause incomplete burning, leading to wasted fuel and reduced mileage.

What happens if I don’t replace my spark plugs?

Ignoring spark plug replacement can lead to misfires, poor acceleration, reduced fuel economy, hard starting, and even damage to the catalytic converter due to unburned fuel.

Can I replace spark plugs myself?

Yes, replacing spark plugs on the 3.5L EcoBoost is a DIY-friendly job with the right tools. Just take your time, follow the steps, and use a torque wrench to avoid over-tightening.