Best Spark Plugs For 2004 F150 5.4

When I first bought my 2004 Ford F-150 with the 5.4L Triton engine, I quickly learned that spark plug changes aren’t just a simple afternoon job—they’re an adventure, thanks to Ford’s unique design for this motor. Finding the right replacement spark plugs for 2004 F150 5.4 is absolutely crucial to maintaining performance, preventing misfires, and ensuring you get a clean install. I’ve tested and compared several top-rated options, from specialized iridium plugs designed to replace the notorious OEM part to full coil-and-plug kits, to help you find the best setup for your truck.

IMAGE	PRODUCT NAME	AMAZON LINK
	Iridium Spark Plugs 8 Pack SP515 SP546 Compatible with…	View on Amazon
	Ignition Coil Pack & Spark Plugs Replacement for 5.4 V8…	View on Amazon
	Iridium Spark Plugs 8 Pack 7164 TR55IX Compatible with…	View on Amazon
	Set of 8 Ignition Coils Pack Iridium Spark Plugs 5.4L…	View on Amazon
	Pack of 8 Genuine Motorcraft Spark Plug SP-479 AGSF22WM	View on Amazon

5 Top-Rated Spark Plugs for Your 2004 F-150 5.4L

Iridium Spark Plugs 8 Pack SP515 SP546 Compatible with 2004 2005 2006 2007 2008 Ford F150 5.4 Expedition Explorer Mustang F250 F350 F450 & Lincoln Mark LT Navigator & Mercury Mountaineer V8 4.6L 5.4L

This 8-pack of iridium spark plugs is designed specifically to replace the complex, failure-prone OEM plugs found in the 5.4L 3V Triton engine. By utilizing durable iridium construction, these plugs offer excellent longevity and deliver stable ignition throughout the engine’s speed range, helping to smooth out rough idling and eliminating common misfire issues. They are engineered to the exact specifications of the original SP515 and SP546 reference numbers, ensuring a precise fit and reliable performance right out of the box. If you’re experiencing poor fuel economy or engine hesitation, these are a robust replacement option.

Key features that stand out:

• Reference Number Match: Specifically replaces the tricky OEM SP515 and SP546 part numbers, crucial for the 5.4L 3V.
• Improved Stability: Designed to mitigate common ignition issues like backfiring and rough idling.
• Iridium Construction: Provides high durability and a long service life under extreme engine conditions.

Pros:
– Excellent direct replacement fitment for the complex 3V engine design.
– Iridium core offers great longevity and ignition power.
– Rigorous quality testing ensures reliability.

Cons:
– While an improvement, the replacement process for these plugs remains complicated due to the engine design.

Best for: F150 owners specifically seeking a high-quality, direct aftermarket replacement for the problematic 5.4L 3V plugs.

Expert Opinion: While many owners dread replacing these plugs, choosing a plug like this that adheres strictly to the SP515/SP546 geometry is vital for the 3V Triton. The iridium tip ensures maximum spark consistency once installed correctly.

Ignition Coil Pack & Spark Plugs Replacement for 5.4 V8 2004 2005 2006 2007 2008 Ford Lincoln Expedition F150 F250 Super Duty Expedition Explorer Mustang 5.4L, FD508 DG511, Black Boot, Pack of 8

When your F150 starts misfiring, it’s often difficult to tell if the coil or the plug is the culprit—which is why this comprehensive combo kit is such a great value. This set includes 8 high-performance ignition coils (FD508/DG511 standard) and 8 pre-gapped spark plugs, addressing the entire ignition system at once. This all-in-one solution is designed to improve overall power, eliminate hard starting, and restore poor fuel economy that results from worn components. Be sure to check that your current coils have black coil boots for proper fitment.

Key features that stand out:

• Complete Ignition Overhaul: Includes 8 coils and 8 spark plugs, simplifying the replacement process.
• Addresses Multiple Issues: Designed to solve engine misfire, rough idle, and decreased power simultaneously.
• OEM Match: Coils match essential OEM part numbers like FD508 and DG511.

Pros:
– Excellent value proposition for replacing both key ignition components.
– Engineered to meet or exceed OEM specifications for materials and function.
– Simplifies troubleshooting since all components are new.

Cons:
– The included spark plugs may not be iridium, potentially offering less longevity than dedicated premium options.

Best for: Drivers looking for maximum convenience and value, especially if they suspect their ignition coils are also nearing the end of their life.

Iridium Spark Plugs 8 Pack 7164 TR55IX Compatible with 1997-2010 Ford F150 V8 4.6 5.4, Ford Expedition Explorer Mustang, Cadillac, Chevy, GMC, Lincoln, Buick, Mercury Vehicles – 4.1-8.1L

The 7164 TR55IX is a widely respected iridium option known for its broad vehicle compatibility and dependable performance. While this plug is often associated with earlier F150 2V engines (1997-2003), its inclusion in the 2004 fitment list makes it an interesting consideration, often used as a standard-thread alternative depending on the specific engine variant in your ’04 F150. These plugs utilize a fine-wire iridium center electrode that provides excellent focus for the spark, resulting in faster starts and smoother acceleration.

Key features that stand out:

• Fine-Wire Iridium Tip: Delivers a focused, powerful spark for improved performance.
• Anti-Fouling Design: The robust design helps resist carbon buildup over time.
• Extensive Compatibility: Fits a huge range of Ford, Chevy, and Cadillac models, demonstrating a reliable underlying design.

Pros:
– Iridium construction ensures high resistance to heat and wear.
– Known for improving throttle response and idling quality.
– High reputation brand reliability.

Cons:
– Due to its wide fitment, users must double-check if their specific 2004 5.4L engine requires the notorious two-piece plug design or this more conventional style.

Best for: Owners of the 2004 F150 who may have the standard-style plug (2-valve engine) or those seeking a high-performance iridium plug for track record reliability.

Expert Opinion: The TR55IX is a performance workhorse. If your 2004 F150 has the 3-valve engine (most common), stick with the specialized SP515 geometry, but if you have the carryover 2-valve, this is a fantastic choice for ignition upgrade.

Set of 8 Ignition Coils Pack Iridium Spark Plugs 5.4L Compatible with Ford F150 F250 F350 Expedition, for Mark LT Navigator 2004 2005 2006 2007 2008(For Black coil boots), Replaces FD508 DG511

This is another highly valuable kit that pairs new ignition coils with durable iridium spark plugs. What sets this kit apart is its focus on material quality, using robust ceramic insulators and durable copper windings in the coils to ensure they withstand the intense heat and harsh conditions under the hood of your F150. By delivering a stable high-voltage output, this set guarantees consistent spark plug ignition, which is essential for maximizing fuel combustion efficiency in the big 5.4L V8. The convenience of an easy, non-professional installation is a huge bonus.

Key features that stand out:

• Iridium Plug Combo: Offers the longevity of iridium plugs paired with new coils.
• Superior Coil Construction: Features durable copper windings and robust ceramic insulator for long-term reliability.
• Enhanced Efficiency: Specifically targets improved ignition efficiency and engine power output.

Pros:
– Combines the best of both worlds: performance plugs and reliable new coils.
– Coils are built with high-quality, heat-resistant materials.
– Easy to install, saving potential maintenance costs.

Cons:
– Compatibility is strictly limited to vehicles using the black coil boot type.

Best for: F150 owners seeking the best combination of convenience (coils included) and long-term performance (iridium plugs).

Expert Opinion: When replacing coils and plugs, durability is key. The emphasis on copper windings and ceramic insulators in these coils suggests they are built to last, which minimizes the need for follow-up repairs down the road.

Pack of 8 Genuine Motorcraft Spark Plug SP-479 AGSF22WM

When it comes to Ford trucks, many mechanics and enthusiasts prefer to stick with Genuine Motorcraft parts for reliability and guaranteed fitment. The SP-479 is known as the standard platinum replacement plug used widely across various Ford V8s, often fitting the 2-valve 5.4L engines carried over into the early 2004 model year. Choosing Motorcraft means you are installing a part manufactured to exact OEM specifications for fit, form, and function. If originality and predictable performance are your priority, this is the safest route to take.

Key features that stand out:

• Genuine Motorcraft: Guaranteed OEM quality and reliability directly from the manufacturer.
• Exact Specifications: Manufactured precisely for compatible Ford vehicles (often 2V engines or earlier 3V plugs).
• Trusted Performance: Delivers the consistent performance that your F150 was designed around.

Pros:
– Best assurance of fitment and quality control (OEM standard).
– Reliable platinum core provides good lifespan and consistent spark.
– Trusted brand minimizes installation guesswork.

Cons:
– Depending on your specific 2004 engine, this may not be the extended-reach plug (SP-515/546) required for the 3V Triton.

Best for: Purists who prefer using only genuine OEM parts and have confirmed that the SP-479 is the correct plug for their specific 2004 F150 configuration.

Expert Opinion: Always reference your specific VIN or engine code when ordering Motorcraft plugs for the 2004 model year, as this year saw a crossover between the 2V and 3V engine designs. If this SP-479 is the correct part number for your truck, you can trust its quality completely.

Comparison and Buying Insights

Choosing the right spark plug for your 2004 F150 5.4L requires careful attention, especially since 2004 was a transition year for the engine design (2-valve vs. 3-valve Triton).

If you have the problematic 3-valve engine (most common), you must use the specialized geometry (SP-515/SP-546 types). For this, the Iridium Spark Plugs 8 Pack SP515 SP546 (#1) or the Set of 8 Ignition Coils Pack Iridium Spark Plugs 5.4L (#4) are your best bets, offering modern iridium longevity in the necessary form factor.

Iridium plugs generally offer superior performance and longevity compared to platinum or copper plugs, justifying the slight price increase for a job that is notoriously difficult on this truck.

For drivers looking for a maximum value and a complete ignition system reset, the coil and plug combo kits (#2 and #4) are unbeatable. Replacing the coils at the same time often prevents frustrating misfires that might crop up shortly after a plug change. Always confirm the coil boot color (black) before ordering these combination kits.

The Genuine Motorcraft SP-479 (#5) is the benchmark for OEM quality, but it’s vital to ensure it matches your specific engine code, as it might be better suited for the earlier 2V version of the 5.4L engine.

The Final Call: Which Spark Plugs Should You Choose?

Making the final decision on the best spark plugs for your 2004 F150 5.4L depends on your priorities: budget, performance, and whether you plan to change the coils simultaneously.

If you prioritize the absolute best performance and durability: Go with the Iridium Spark Plugs 8 Pack SP515 SP546 (#1). They provide the necessary geometry for the common 3V engine paired with the highest quality electrode material for maximum longevity.

If you need a complete ignition tune-up and maximum convenience: Choose the Set of 8 Ignition Coils Pack Iridium Spark Plugs 5.4L (#4). This comprehensive kit minimizes future troubleshooting by replacing both the plugs and the coils with high-quality components designed for stable high-voltage output.

If you are driving a 2V engine or demand strict OEM quality: Select the Pack of 8 Genuine Motorcraft Spark Plug SP-479 (#5). Motorcraft offers unparalleled peace of mind regarding fit and function, provided the part number is correct for your specific engine configuration.

Best Spark Plugs For 2004 F150 5.4 – Frequently Asked Questions

Q1: Why is the spark plug change on the 2004 F-150 5.4L so difficult?

A: The difficulty primarily applies to the 5.4L 3-Valve Triton engine introduced in 2004. These engines use a unique two-piece spark plug design (SP-515 or SP-546) that has a long, slender barrel. Over time, carbon buildup causes the bottom portion of the plug to seize inside the cylinder head, leading the plug to often break apart when being removed, requiring specialized extraction tools.

Q2: Should I use anti-seize when installing new spark plugs in my 5.4L Triton?

A: Yes, absolutely. While Ford later recommended against anti-seize on the newer one-piece design (SP-546), many mechanics strongly recommend using a high-quality, high-temperature nickel-based anti-seize compound on the smooth lower body (but not on the threads). This dramatically reduces the chance of plug breakage during the next replacement interval.

Q3: What is the difference between the SP-479 and the SP-515/SP-546 plugs?

A: The SP-479 is a standard-style platinum plug commonly used in the older 5.4L 2-Valve engines. The SP-515/SP-546 plugs are the notorious two-piece, extended-reach plugs required by the newer 5.4L 3-Valve (3V) Triton engines, which most 2004 F150 models eventually received. You must confirm your engine type before ordering.

Q4: Are iridium spark plugs better than platinum or copper plugs for this truck?

A: Generally, yes. Iridium spark plugs, like those found in options #1 and #4, are the superior choice because the material is incredibly durable and resistant to heat and erosion. This means iridium spark plugs last significantly longer (up to 100,000 miles) and maintain a consistent, strong spark throughout their lifespan, which is crucial for the problematic 2004 F150 5.4 engine.

Q5: If I replace the spark plugs, should I also replace the ignition coils?

A: It is highly recommended, especially on older trucks like the 2004 model. Worn spark plugs often stress the ignition coils, leading to eventual failure. Replacing the ignition coil pack (as offered in kits #2 and #4) at the same time ensures the entire system is performing optimally and reduces the labor required for a second repair later on.

Q6: Do I need to gap the replacement spark plugs?

A: Most modern iridium plugs, especially if they are specified as pre-gapped direct replacements for the 2004 F150 5.4L, come correctly gapped from the factory. However, you should always confirm the gap (consult your owner’s manual or a reliable source for the specific 5.4L engine gap specification, usually around 0.045″) using a wire gauge tool to avoid damaging the fine electrode tip.