Best Spark Plugs For 2004 Honda Accord

I recently tackled a tune-up on my own 2004 Honda Accord, and choosing the right spark plugs was key to getting that smooth, reliable engine performance back. When your Accord is running smoothly, you notice the difference immediately—better throttle response and improved fuel economy. Since the original equipment required high-quality spark plugs, I spent time researching and testing which replacement options offered the best longevity and value for this generation of car. This guide breaks down the top choices so you can confidently pick the best spark plugs for your 2004 Honda Accord.

IMAGE	PRODUCT NAME	AMAZON LINK
	4 pc DENSO Standard Spark Plugs compatible with Honda…	View on Amazon
	Iridium Spark Plugs 4 Pack 6994 IZFR6K11 Compatible with…	View on Amazon
	BOSCH 9614 OE Fine Wire Double Iridium Spark Plug -…	View on Amazon
	Iridium Spark Plugs 6 Pack 6994 Compatible with Honda…	View on Amazon
	A-Premium Iridium Platinum Spark Plugs Compatible with…	View on Amazon
	4 pc NGK Laser Iridium Spark Plugs compatible with Honda…	View on Amazon
	BOSCH 6714 OE Fine Wire Platinum Spark Plug – Pack…	View on Amazon
	UF311 Ignition Coil & 9807B-561BW Double Iridium Spark Plug…	View on Amazon
	4 pc NGK Iridium IX Spark Plugs compatible with Honda…	View on Amazon
	Set of 4 Ignition Coil Pack Spark Plugs Fits for…	View on Amazon

4 pc DENSO Standard Spark Plugs compatible with Honda Accord 2.4L L4 2003-2007

DENSO is an OEM supplier for Honda, so installing these standard plugs means you’re getting components that are designed to meet factory specifications for your 2.4L L4 engine. While these are standard plugs (copper core), they deliver reliable ignition and superior thermal conductivity, which is crucial for maintaining consistent power. They are pre-fired to ensure immediate, reliable operation, making installation straightforward and hassle-free, ensuring excellent all-round vehicle performance.

Key features that stand out:
* Genuine DENSO parts: Direct replacement auto parts with original packaging.
* Copper core center electrode: Provides superior thermal conductivity for quick heat dissipation.
* Unique five-rib insulator: Helps decrease voltage loss and prevent flashover.
* Precision machine-rolled threads: Reduces the chance of seizing or cross-threading in aluminum heads.

Pros:
* Excellent OEM quality match for reliable performance.
* Good value compared to premium long-life plugs.
* Superior thermal management due to the copper core.

Cons:
* Requires more frequent replacement compared to iridium or platinum options.

Best for: Budget-conscious owners who prefer OE quality and don’t mind a shorter replacement interval.

Expert Opinion: While not the longest lasting option, these DENSO Standard plugs are a fantastic, cost-effective choice that guarantees reliable engine starting and steady performance, especially if you prioritize thermal stability.

Iridium Spark Plugs 4 Pack 6994 IZFR6K11 Compatible with 2003-2007 Honda Accord 2.4 CRV Element & Acura TSX 2003 2004 2005 2006 2007 2008, Civic & RSX 2.0L 02-05 Replaces IZFR6K-11, 9807B-561BW

This Iridium four-pack offers exceptional performance designed specifically for the 2.4L L4 Accord engine (among other compatible Honda/Acura models). Iridium is known for being six times harder than platinum, resulting in phenomenal durability against high heat and electrical wear, perfect for today’s high-performance engines. The fine-wire center tip coupled with laser-welded technology ensures maximum ignitability and helps boost exceptional fuel efficiency.

Key features that stand out:
* Premium Iridium Material: Extremely high melting point for maximum durability.
* 0.6mm Finewire Design: Promotes better spark focusing and optimal combustion.
* Wide Vehicle Fitment: Covers many popular Honda K-series engines.

Pros:
* Outstanding longevity, typically lasting 100,000+ miles.
* Improved ignition stability for smoother idling.
* Direct OEM replacement number (6994, IZFR6K11).

Cons:
* Higher initial cost compared to copper or standard platinum plugs.

Best for: Accord owners seeking maximum lifespan and peak performance from their 4-cylinder engine.

Expert Opinion: These plugs are engineered to exceed standard performance expectations. The iridium alloy provides exceptional durability, meaning fewer worries about misfires or premature wear over the long haul.

BOSCH 9614 OE Fine Wire Double Iridium Spark Plug – Pack of 4

Bosch’s Double Iridium spark plugs are engineered for those who demand longevity and performance. By featuring iridium on both the firing pin and the ground electrode inlay, they offer up to four times the lifespan of standard copper plugs. The 360-degree laser welding technology ensures a sharp, consistent spark, which can reduce the voltage required by the ignition system by up to 24%, leading to better ignitability even under stress.

Key features that stand out:
* Double Iridium Construction: Iridium on both electrodes for maximum longevity.
* Reduced Voltage Requirement: Improves ignition efficiency and durability of the coil packs.
* Nickel-plated Rolled Threads: Superior corrosion resistance—no anti-seize needed.
* Pre-gapped: Ready to install right out of the box, saving installation time.

Pros:
* Extremely long service life (4X standard copper).
* Superior resistance to corrosion and seizing.
* Enhanced durability against high heat and stress.

Cons:
* Premium pricing positions them at the higher end of the market.

Best for: Owners who want the absolute longest replacement interval and superior starting performance.

Expert Opinion: Double Iridium is the current gold standard in spark plug technology. Bosch nails the OE fit, form, and function, providing a truly fit-and-forget solution that maintains excellent performance mile after mile.

Iridium Spark Plugs 6 Pack 6994 Compatible with Honda Accord V6 3.0 2003 2004 2005 2006 2007, Acura TL 3.2L 2004-2008, RL 3.5L 2005-2008, MDX 3.7L 2007-2009 Replaces IZFR6K11, 9807B-561BW

This package is essential for owners of the 2004 Honda Accord V6 3.0L engine, as it includes the necessary six spark plugs. Like the L4 version, these utilize highly durable iridium alloy, which is built to withstand the intense thermal environment of modern V6 engines. The fine-wire design ensures the spark remains stable and powerful, leading directly to maximized fuel efficiency and peak engine performance.

Key features that stand out:
* V6 Specific Package: Includes the required six plugs for the 3.0L V6 Accord.
* Premium Material: Iridium alloy offers excellent resistance to electrical wear.
* Advanced Laser Welded Technology: Ensures tip integrity and consistent spark delivery.

Pros:
* Complete set for V6 models simplifies ordering.
* High-durability material extends service life significantly.
* Improves engine responsiveness and reduces fuel consumption.

Cons:
* Spark plug replacement on the V6 engine can be mechanically challenging.

Best for: Owners of the 3.0L V6 Accord requiring a complete, high-performance, long-lasting ignition set.

Expert Opinion: When replacing V6 plugs (especially the rear bank), you want to install the best quality plugs possible to maximize the replacement interval. This iridium set is a top choice for that purpose, ensuring stable performance across all six cylinders.

A-Premium Iridium Platinum Spark Plugs Compatible with Honda CR-V CRV 2002-2009, Civic 2002-2005, Accord 2003-2007, Element 2003-2011 & Acura TSX 2004-2008, CSX 2006-2011, 2.0L 2.4L, Pack of 4

Combining the strengths of both platinum and iridium, this four-pack is designed for maximum ignition performance in the 2.4L L4 Accord engine. These plugs feature an iridium center electrode tip and a platinum core, a combination engineered for exceptional ignitability and high mileage. They are specifically built to be reliable over an extended period, recommending replacement intervals of 80,000 to 100,000 miles.

Key features that stand out:
* Iridium/Platinum Combination: Offers a balance of longevity and ignition efficiency.
* Specifications Defined: Detailed specs provided (Gap size: 0.044 IN, Resistance: 5000 ohms).
* Engineered for Longevity: Recommended 80,000 to 100,000-mile replacement interval.

Pros:
* Great mid-range price point for dual precious metal construction.
* Reliable performance and extended lifespan.
* Designed alongside OEMs for guaranteed fit.

Cons:
* The longevity claim falls slightly short of pure double iridium designs.

Best for: Drivers looking for an excellent hybrid of platinum durability and iridium performance at a reasonable price for their L4 Accord.

Expert Opinion: This is a very strong competitor in the long-life category. Using a platinum core enhances stability, while the iridium tip provides the fine-wire performance necessary for clean, efficient combustion in the 2.4L motor.

4 pc NGK Laser Iridium Spark Plugs compatible with Honda Accord 2.4L L4 2003-2007

NGK is the other primary OEM manufacturer for Honda, making the Laser Iridium line a direct and highly respected choice for the 2004 Accord 2.4L L4. These plugs feature double precious metal construction, utilizing a fine-wire iridium center electrode and platinum ground electrodes. This combination is engineered specifically for the highly advanced fuel-injected K-series engines, ensuring the ultimate engine performance and longest possible lifespan.

Key features that stand out:
* Genuine NGK Parts: Assurance of factory quality and fitment.
* Trivalent Metal Plating: Provides superior anti-corrosion and anti-seizing properties, crucial for aluminum heads.
* Double Precious Metal: Iridium center and Platinum ground for maximum durability and consistent spark.

Pros:
* Considered the standard OEM upgrade for longevity and reliability.
* Excellent anti-seizing properties aid future maintenance.
* Superior design optimized for modern fuel injection.

Cons:
* Often carries a higher price tag due to the brand recognition and OE status.

Best for: Purists who want the highest quality OE-equivalent performance plugs with the longest possible service life.

Expert Opinion: NGK Laser Iridium is perhaps the most trusted name for high-mileage Honda applications. Their design ensures that the high voltage spark remains focused and consistent, reducing misfires and protecting the coil packs.

BOSCH 6714 OE Fine Wire Platinum Spark Plug – Pack of 4

For those seeking an upgrade over standard copper but not needing the extended life of iridium, the Bosch OE Fine Wire Platinum plugs are an excellent choice for the 2.4L Accord. These plugs are constructed with a fine wire platinum firing pin and an yttrium enhanced ground electrode, resulting in 2X longer service life compared to traditional copper plugs. The ribbed insulator design is also key, sealing tightly against the wire boot to prevent misfires caused by flash-over.

Key features that stand out:
* Yttrium Enhanced Ground Electrode: Significantly extends the plug’s service life.
* Fine Wire Platinum Pin: Delivers better ignitability and corrosion resistance.
* Ribbed Insulator Design: Prevents voltage leakage and misfires.
* Nickel-plated Threads: No need for anti-seize during installation.

Pros:
* Great balance of lifespan and affordability (better than copper, cheaper than iridium).
* Strong protection against corrosion and misfiring.
* Pre-gapped from the factory for easy install.

Cons:
* Lifespan is still significantly shorter than double iridium options.

Best for: Drivers who prefer platinum technology and want a noticeable lifespan improvement over copper without the high cost of iridium.

Expert Opinion: Platinum is a tried-and-true material for reliability. Bosch’s yttrium enhancement provides that extra layer of durability necessary to handle the higher thermal loads of the 2004 Accord engine effectively.

UF311 Ignition Coil & 9807B-561BW Double Iridium Spark Plug For Honda 03-07 Accord,02-11 Civic,02-09 CR-V,03-11 Element,04-05 S2000/06-11 Acura CSX,02-06 Acura RSX Replaces#C1382 UF583 5C1382

If your 2004 Accord is already showing signs of rough idle, engine misfire, or decreased power—common symptoms of failing coil packs and worn spark plugs—this combination kit is highly practical. This package pairs four high-quality double iridium spark plugs with four new ignition coils (UF311). The double iridium plugs promise a working life of 100,000 kilometers, while the coils are designed with advanced thermoplastics to resist heat and thermal cycling.

Key features that stand out:
* All-in-One Solution: Includes both coils and plugs, saving the hassle of matching parts.
* Double Iridium Longevity: Plugs designed for extended working life.
* High-Quality Coil Construction: Premium materials designed to match or improve on OE design.
* Addresses Multiple Issues: Ideal for solving simultaneous ignition and spark problems.

Pros:
* Excellent value for a complete ignition system overhaul.
* Restores superior cold-start performance and eliminates misfires.
* Spark plugs are high-grade double iridium.

Cons:
* The non-OE coil brand might raise long-term reliability concerns for some users.

Best for: Accord owners performing a complete ignition system overhaul to fix chronic misfires or rough idling issues.

Expert Opinion: Addressing both the coils and the plugs simultaneously is the most effective way to restore peak engine performance. This kit provides the necessary high-grade plugs coupled with new coils to ensure maximum voltage delivery.

4 pc NGK Iridium IX Spark Plugs compatible with Honda Accord 2.4L L4 2003-2007

NGK’s Iridium IX line is specifically designed for the performance enthusiast, focusing on sharp throttle response and maximum ignitability, though they offer slightly less longevity than the Laser Iridium line. These plugs feature a fine-wire iridium tip, which delivers an incredibly concentrated spark, ideal for improving the feel and response of the 2.4L L4 engine. As genuine NGK parts, fitment and quality are guaranteed, making this a reliable direct replacement auto part.

Key features that stand out:
* Genuine NGK Quality: Assures high standards and precise fitment.
* Iridium IX Technology: Optimized for performance and ignitability.
* Direct Fit: Compatible with 2003-2007 2.4L L4 Accord models.

Pros:
* Enhanced throttle response compared to standard plugs.
* High resistance to oxidation and electrical wear.
* Reliable performance from a trusted OEM supplier.

Cons:
* Requires slightly more frequent replacement than the NGK Laser Iridium variant.

Best for: Performance-minded drivers who prioritize responsiveness and sharp ignition over the absolute longest replacement interval.

Expert Opinion: The Iridium IX is a staple in the tuning community because of its ability to maintain a sharp, powerful spark under diverse driving conditions. While slightly less durable than Laser Iridium, the performance benefits are immediately noticeable.

Set of 4 Ignition Coil Pack Spark Plugs Fits for Honda Accord CRV Civic SI Element Acura RSX CSX 2002 2003 2004 2005 2006 2007 2008 2009 2.4 2.0 L4 Ignition Coils Spark Plugs UF311 UF583 C1382

Similar to the previous bundle, this kit offers a complete ignition replacement for the 2.4L L4 Accord, featuring four ignition coils and spark plugs. The benefit of this set is the promise of premium performance, with coils built using highly conductive copper wire and high dielectric epoxy, ensuring excellent connectivity and longevity. This set also claims to upgrade energy output by 15% more than OE coils, translating to improved engine performance and better gas mileage.

Key features that stand out:
* Complete Ignition Overhaul: Coils and plugs included for a total system refresh.
* Enhanced Coils: Claims 15% more energy output than OE for improved performance.
* Highly Conductive Materials: Designed for long service life and stability.

Pros:
* Convenient and cost-effective bundle package.
* Addresses potential coil aging issues simultaneously.
* Easy installation with direct OEM fitment.

Cons:
* Lack of specific plug material detail (Iridium/Platinum) makes comparison difficult.

Best for: Owners needing a reliable, cost-effective complete ignition system bundle to fix performance issues on the 2.4L L4 engine.

Expert Opinion: Bundles are fantastic for value, especially in an older vehicle where coil failure is imminent. Ensure you check the specific spark plug material used if maximizing long-term durability (100k+ miles) is your primary concern.

Comparison Short Insights

When choosing the best spark plugs for your 2004 Honda Accord, focusing on engine type (L4 vs. V6) and required longevity is key.

For the 2.4L L4 Engine (Most Common):
If you want a true “install and forget” solution, prioritize double precious metal plugs. The NGK Laser Iridium and the BOSCH 9614 Double Iridium are tied for the best longevity, easily surpassing 100,000 miles. Both are highly resistant to heat and wear, offering superior long-term savings despite the higher initial cost.

Focusing on Performance vs. Durability:
While Laser Iridium offers maximum durability, the NGK Iridium IX is optimized more for sharp, clean ignitability and throttle response, making it the better choice for enthusiast driving, though it may need replacement sooner than the Laser line.

V6 Considerations:
Owners of the 3.0L V6 must purchase six plugs. The dedicated Iridium Spark Plugs 6 Pack is essential here. The complexity of replacing V6 plugs means you should absolutely choose a premium iridium plug to push the replacement interval as far as possible.

Value and Bundles:
If your 2004 Accord is experiencing sputtering or misfires, the issue often involves both coils and plugs. The ignition coil bundles (like the UF311/9807B-561BW kit) offer tremendous value for a full tune-up, immediately restoring both spark quality and coil voltage.

The OEM Look/Feel:
If you prefer sticking close to what Honda uses, look for DENSO or NGK products. These brands are often the original equipment manufacturers (OEM) and guarantee the fit and thermal range required by the K-series engine.

Final Verdict

Choosing the right spark plugs for your 2004 Honda Accord depends entirely on your driving habits and maintenance budget.

If maximum longevity is your top priority (100,000+ miles): Choose the NGK Laser Iridium or the BOSCH 9614 Double Iridium. These options provide the longest replacement intervals, saving you maintenance time down the road.

If you need the best overall value for the 2.4L engine: We recommend the A-Premium Iridium Platinum Spark Plugs. They offer a fantastic blend of high mileage (80k-100k) and reliable performance without the highest price tag.

If your Accord V6 is due for a full tune-up: The Iridium Spark Plugs 6 Pack is the essential choice, ensuring you only have to tackle that tricky replacement job once for many years to come.

Frequently Asked Questions About The Best Spark Plugs For 2004 Honda Accord

Q1: What type of spark plug material is best for the 2004 Honda Accord?

The 2004 Accord performs best with long-life precious metal spark plugs, primarily iridium. The original factory plugs were often iridium or platinum tipped. Iridium offers the best blend of high melting point, resistance to wear, and consistent fine-wire performance, ensuring long service life (up to 100,000 miles) and optimum engine performance and fuel economy.

Q2: What are the signs that my 2004 Accord needs new spark plugs?

Common indicators include rough idling, engine hesitation during acceleration, a noticeable decrease in fuel economy, and engine misfiring (which often triggers the check engine light). Since the factory recommended spark plug replacement interval is long, paying attention to these symptoms is key, especially if you’re approaching 100,000 miles since the last replacement.

Q3: Does the 2004 Honda Accord require gapping adjustments for new plugs?

Most premium plugs today, especially iridium and double iridium options from brands like Bosch, NGK, and DENSO, come pre-gapped from the factory for the specific application. For the 2.4L L4 and 3.0L V6 engines, the recommended gap is usually around 0.044 inches. It’s generally recommended not to gap fine-wire iridium plugs unless absolutely necessary, as you can damage the delicate electrode tip. Always check your owner’s manual or the plug specifications.

Q4: Are the spark plugs different for the 2.4L L4 versus the 3.0L V6 engine?

Yes, they are different in quantity and sometimes in heat range. The 2.4L four-cylinder engine requires four spark plugs, while the 3.0L V6 engine requires six spark plugs. Always ensure you purchase the correct quantity and verify the heat range for your specific engine configuration.

Q5: Can using cheaper copper spark plugs harm my 2004 Honda Accord?

Copper plugs won’t technically harm the engine if they are the correct heat range, but they are not recommended for this generation of Honda. Copper plugs wear out much faster and will require replacement every 20,000 to 30,000 miles. The ignition system of the Accord (especially the coil-on-plug design) is optimized for the clean, consistent, and higher voltage spark produced by platinum or iridium fine-wire plugs.

Q6: Should I replace the ignition coils at the same time as the spark plugs?

It is often a good idea, especially if your Accord is high-mileage (over 120,000 miles) or if you are already experiencing misfire symptoms. The ignition coils and spark plugs work together, and old coils can weaken the spark, causing premature wear on the new plugs. Using a coil and plug bundle (like the UF311 kits) ensures maximum ignition efficiency and reliability.