Best Spark Plugs For 2004 Mustang GT

When I first bought my ’04 GT, I knew the 4.6L V8 engine needed fresh life. Upgrading the ignition system is one of the easiest ways to recapture lost power and efficiency. If you’re hunting for the best spark plugs for 2004 Mustang GT, you’ve come to the right place. We’ve compiled detailed reviews on top replacement options to help you choose the right plug type—whether you prioritize long-term durability or immediate performance gains.

IMAGE	PRODUCT NAME	AMAZON LINK
	A-Premium Iridium Platinum Spark Plugs Compatible with Ford…	View on Amazon
	8 pc NGK V-Power Spark Plugs compatible with Ford Mustang…	View on Amazon
	SCITOO Platinum Iridium Spark Plugs 4477 for Ford for…	View on Amazon
	NGK Iridium Spark Plug TR55IX (8 Pack) for FORD MUSTANG…	View on Amazon
	6 pc NGK V-Power Spark Plugs compatible with Ford Mustang…	View on Amazon
	GPMMWPG Ignition Coil Pack and Spark Plugs Compatible with…	View on Amazon
	New Motorcraft SP547 Spark Plug (8 PACK) Finewire Platinum	View on Amazon

A-Premium Iridium Platinum Spark Plugs Compatible with Ford F-150 1999-2003, Mustang 2003-2004 2007-2012, GT 2005-2006, Crown Victoria 1996-2005, 4.6L 5.4L, Pack of 8

The A-Premium spark plugs offer a blend of materials for durability and strong ignition. Utilizing iridium on the center tip and platinum on the core, these are engineered to provide a consistent, high-energy spark while ensuring impressive longevity. They are designed as a direct OEM replacement, meaning installation is straightforward for the standard 4.6L motor. These are a fantastic option if you want reliable performance without breaking the bank.

Key features that stand out:
– Center Electrode Tip Material: Iridium
– Center Electrode Core Material: Platinum
– Engineered for Longevity: Recommended replacement interval of 80,000 to 100,000 miles
– Exact Fitment: OE design ensures they drop right into the 2004 Mustang GT 4.6L V8.

Pros:
– Long lifespan thanks to the iridium/platinum combination.
– Provides exceptional ignitability for quick starts.
– Cost-effective option compared to major brand dual-metal plugs.

Cons:
– Some users prefer major brand assurance over aftermarket equivalents.

Best for: Drivers seeking maximum plug life and reliability for their daily driven GT.

Expert Opinion: This plug design, leveraging both iridium and platinum, is great for maximizing the time between service intervals. It offers a very stable idle and consistent firing across temperature ranges, closely matching OEM durability standards.

8 pc NGK V-Power Spark Plugs compatible with Ford Mustang 4.6L 5.0L V8 1993-2004

NGK V-Power plugs are the go-to for many enthusiasts who still prefer a copper core plug, especially if they plan on changing them more frequently or if they have mild modifications. These plugs use a unique V-cut ground electrode, which directs the spark to the edge of the center electrode, reducing quenching and improving ignitability. For the performance-minded owner who wants a consistent, strong spark, this is an affordable classic.

Key features that stand out:
– Copper Core: Excellent conductivity for a powerful spark.
– V-Cut Ground Electrode: Improves sparking and reduces misfires.
– Genuine NGK Parts: Trusted brand for high-quality ignition components.
– Direct Replacement: Specifically fits the 4.6L V8 in your 2004 GT.

Pros:
– Excellent spark energy due to copper’s conductivity.
– Affordable and reliable performance option.
– Proven track record in performance applications.

Cons:
– Copper plugs require replacement more frequently (typically every 30,000 miles).

Best for: Budget-conscious drivers or those who prioritize maximum conductivity for quick bursts of performance.

Expert Opinion: NGK V-Power plugs are foundational for performance tuning. While they don’t last as long as iridium, their strong, consistent spark delivery is unmatched by materials like platinum, making them popular with people who frequently check and replace their plugs.

SCITOO Platinum Iridium Spark Plugs 4477 for Ford for F-150 1999-2003, for Mustang 2003-2004 2007-2012, GT 2005-2006, Crown Victoria 1996-2005, 4.6L 5.4L Pack of 8

SCITOO offers another great dual-material spark plug option designed for the Ford Mod Motor family, including the 4.6L V8 found in the 2004 Mustang GT. The combination of iridium and platinum ensures the engine maintains a stable idle and faster starting capability. These are manufactured to OE specifications, meaning you get the exact fit and function required for easy, reliable installation. They focus on delivering a stable, long-lasting performance solution.

Key features that stand out:
– Dual-Metal Construction: Combines Platinum and Iridium for longevity.
– Stable Idle: Designed to improve combustion stability and starting performance.
– OE Design: Ensures exact form, fit, and function for your vehicle.
– Cross-Reference Capability: Replaces several common Ford/Mazda part numbers (4477, ITR6F13, etc.).

Pros:
– Excellent value for an 8-pack of iridium/platinum plugs.
– Improves engine start-up and stability.
– Direct drop-in installation.

Cons:
– Longevity claims might not perfectly match those of premium brands like NGK or Motorcraft.

Best for: Buyers looking for a great value, high-mileage spark plug alternative to the A-Premium option.

Expert Opinion: These plugs are engineered to serve the core function of stable, high-voltage ignition over many miles. Iridium’s role in resisting wear is crucial for these longer-life plugs, making them ideal for someone who hates frequent maintenance.

NGK Iridium Spark Plug TR55IX (8 Pack) for FORD MUSTANG GT 1996-2004 4.6L/281

When you talk about performance and durability, NGK Iridium IX plugs are often at the top of the list. Specifically designed for the 4.6L V8 engine code, the TR55IX uses a fine wire iridium tip and a copper core for incredible resistance to heat and wear, while still maintaining excellent conductivity. The projected insulator type is specifically used to keep the tip cleaner by exposing it to hotter combustion gases, ensuring consistent firing in performance applications.

Key features that stand out:
– Iridium Electrode Tip: Provides extreme durability and a concentrated spark.
– Copper Core Material: Balances heat resistance with high electrical conductivity.
– Projected Insulator: Helps maintain optimal operating temperature and prevents fouling.
– Manufacturer Heat Range 5: A suitable heat range for stock or mildly modified 4.6L engines.

Pros:
– Industry-leading quality from a top-tier brand.
– Exceptional acceleration response and ignition stability.
– Very long service life (often 80k+ miles).

Cons:
– They sit at a higher price point than standard platinum or copper plugs.

Best for: Enthusiasts who demand premium brand quality, performance, and long-term reliability.

Expert Opinion: The TR55IX is arguably the gold standard for performance street vehicles. If you have any plans for mild modifications like cold air intakes or performance tunes on your 2004 Mustang GT, the robust, stable spark provided by iridium is a significant advantage.

6 pc NGK V-Power Spark Plugs compatible with Ford Mustang 3.8L 3.9L V6 1998-2004

Note: While this product is for the V6 Mustang, we include it here as a cautionary item for 2004 GT owners to ensure they select the correct 8-cylinder pack.

This 6-pack of NGK V-Power plugs is an excellent choice for V6 Mustang owners from 1998 to 2004. These plugs offer the same great copper core conductivity and V-cut design found in the 8-cylinder version. If you accidentally purchase these for your 2004 GT 4.6L, you’ll be short two plugs! Always confirm your engine type (V8 uses 8 plugs) before purchasing.

Key features that stand out:
– Genuine NGK V-Power: Highly reliable, performance-focused copper plug.
– Excellent Conductivity: Delivers strong spark energy.
– Correct Fitment: Designed specifically for the V6 3.8L/3.9L models.

Pros:
– Affordable and provides great short-term performance gains for V6 owners.

Cons:
– Only 6 plugs are included, making them incompatible with the GT V8 model.

Best for: Included purely as a reminder to double-check your engine size (GT requires 8 plugs).

GPMMWPG Ignition Coil Pack and Spark Plugs Compatible with Ford Mustang 1999-2014, 4.6L 1999-2004, 5.4L 2007-2012, 5.8L 2013-2014, GT 2005-2006, Spark Plugs Coil Packs Replaces# UF191 6708 Set of 8

Sometimes, when you replace the plugs, it’s wise to refresh the ignition coils too, especially on an older 4.6L engine where coils commonly fail. This comprehensive kit from GPMMWPG includes 8 double iridium spark plugs and 8 high-performance ignition coils. The double iridium plugs are rated for up to 100,000 km, providing long life, while the coils are designed to deliver up to 15% stronger spark energy than standard OEM units, ensuring maximum combustion efficiency.

Key features that stand out:
– Complete Ignition Overhaul: Includes 8 coils and 8 iridium plugs.
– Double Iridium Plugs: Provides maximum durability and service life.
– Enhanced Coil Performance: Delivers up to 15% stronger spark energy.
– Quality Construction: Coils feature upgraded copper windings and heat-resistant materials.

Pros:
– A total ignition system replacement in one package, saving labor later.
– High-performance coils improve throttle response and fuel efficiency.
– Exceptional value considering the inclusion of 8 coils.

Cons:
– Coils can sometimes be a mixed bag regarding long-term reliability compared to top-tier brands.

Best for: Owners addressing misfires who need to replace both coils and plugs simultaneously for a full ignition refresh.

Expert Opinion: When a 2004 Mustang GT starts showing signs of misfires, it’s often a coil or a plug. Replacing both at the same time is proactive maintenance. This kit offers fantastic bang for the buck and the improved spark energy can definitely be felt in everyday driving.

New Motorcraft SP547 Spark Plug (8 PACK) Finewire Platinum

For many vehicle owners, going with Genuine OEM Parts is non-negotiable, and for the 2004 Mustang GT, that means Motorcraft. The Motorcraft SP547 is a Finewire Platinum plug, designed specifically to meet Ford’s exact quality, reliability, and durability standards for the 4.6L V8 engine. Platinum offers excellent wear resistance, ensuring your maintenance intervals stay long and your engine runs exactly as the factory intended.

Key features that stand out:
– Genuine OEM Quality: Ensures perfect compatibility and factory performance standards.
– Finewire Platinum Tip: Highly resistant to erosion and wear.
– Reliability and Durability: Designed for the longevity expected from factory parts.
– Exact Specifications: Matches the original spark plug installed in the vehicle.

Pros:
– Guaranteed factory fit and function.
– Excellent reputation for durability and longevity.
– The safest choice for maintaining factory warranty or specifications.

Cons:
– Generally doesn’t provide the slight performance edge offered by iridium plugs.

Best for: Purists and owners who prioritize 100% factory specifications and OEM reliability above all else.

Expert Opinion: If you are running a bone-stock 2004 Mustang GT and just want the most reliable, longest-lasting plug that Ford recommends, you stop here. Motorcraft plugs are engineered specifically for that engine’s heat range and compression, ensuring zero compatibility issues.

Comparison Insights: Choosing the Right Plug Type

When selecting the best spark plugs for 2004 Mustang GT, the choice usually comes down to material and maintenance frequency.

For Maximum Longevity and Heat Resistance, the Iridium and Platinum options like the NGK Iridium TR55IX or the A-Premium Iridium Platinum plugs are superior. These plugs maintain a smaller, more concentrated spark over long periods, often lasting 80,000 to 100,000 miles. They are the ideal choice for those who want to “install and forget.”

If you are focused on Pure Conductivity and Performance, the copper V-Power plugs from NGK (8 pc V-Power) deliver the hottest, strongest spark due to copper’s excellent electrical properties. However, you must be willing to change them more often, usually around 30,000 miles. This is a common choice for owners who track their cars or frequently tune their engines.

The Motorcraft SP547 is the guaranteed OE Fit and Function choice. It’s tough to beat factory parts for general reliability and perfect heat range matching, though they may lack the tiny efficiency boost offered by fine-wire iridium competitors.

Finally, if you have a high-mileage GT and are experiencing engine stuttering or misfires, the GPMMWPG coil and plug kit provides an all-in-one ignition overhaul, which is often the most economical way to restore peak performance to an aging 4.6L V8.

Final Verdict: Our Recommendations for Your ’04 GT

Making the right choice for your 2004 Mustang GT ignition system depends entirely on your driving habits and maintenance goals. We’ve broken down the best options into clear categories:

The Overall Street Performance Champion: We recommend the NGK Iridium Spark Plug TR55IX. It combines the superior longevity of iridium with the trusted performance engineering of NGK, offering a great spark for both stock and mildly tuned engines over a maximum service life.

The Best Budget-Conscious Performer: The 8 pc NGK V-Power Spark Plugs are unbeatable if you don’t mind the shorter replacement interval. You get strong spark conductivity for excellent response at a fraction of the cost of iridium.

The Safest Bet (Factory Stock): You can’t go wrong with the New Motorcraft SP547 Spark Plug (8 PACK) Finewire Platinum. It provides the peace of mind that comes with using genuine Ford parts, ensuring perfect compatibility and durability as intended by the manufacturer.

FAQ: Best Spark Plugs For 2004 Mustang GT

What is the correct spark plug gap for a 2004 Mustang GT 4.6L V8?

For the 4.6L V8 engine in the 2004 Mustang GT, the standard spark plug gap is typically 0.054 inches (or 1.35mm). While many modern plugs come pre-gapped, you should always double-check and adjust the gap manually before installation to ensure optimal performance and prevent misfires.

How often should I replace the spark plugs in my 2004 Mustang GT?

The replacement interval depends heavily on the plug material:
* Copper plugs (V-Power): Every 30,000 miles.
* Platinum/Iridium plugs: Every 80,000 to 100,000 miles.
Since the 4.6L Mod Motor is relatively easy to service, using long-life iridium plugs is a popular choice for reducing maintenance frequency.

Should I choose Iridium or Copper spark plugs for better performance?

Copper has superior electrical conductivity, leading to a momentarily stronger spark. However, Iridium is generally better for modern street performance. Iridium allows for a fine-wire center electrode that requires less voltage to fire, ensuring a consistent, strong spark that resists wear and high heat, especially under boost or heavy load.

Do I need special tools to change the spark plugs on a 4.6L Mustang?

Changing spark plugs on the 2004 GT 4.6L V8 is relatively straightforward. You’ll need a spark plug socket (typically 5/8 inch), a ratchet with extensions, and often a torque wrench to ensure you tighten the plugs to the correct torque specs (usually around 11–13 ft-lbs for tapered plugs) to prevent loosening or damage to the cylinder head threads.

What are the signs that my 2004 Mustang GT needs new spark plugs?

Common signs include rough idling, difficulty starting, noticeable decrease in fuel efficiency, slow acceleration, or the engine experiencing frequent misfires (often indicated by a flashing Check Engine Light). Old spark plugs are a leading cause of poor performance in the 4.6L Mustang engine.

Is the heat range important when selecting spark plugs?

Yes, the heat range is crucial for the durability and operation of your engine. The heat range determines how quickly the plug dissipates heat from the combustion chamber. Running a plug that is too “hot” (slow heat dissipation) can cause pre-ignition, while a plug that is too “cold” (fast heat dissipation) can lead to fouling. For most stock 4.6L V8s, sticking to the manufacturer’s recommended heat range (like NGK’s 5 heat range) is essential.