Top 10 Best Spark Plugs For Infiniti FX35 Guide 2025

I’ve spent years wrenching on VQ engines, and when it came time to tune up my Infiniti FX35, choosing the right ignition components was critical. A fresh set of quality spark plugs makes a massive difference in throttle response, fixing those irritating cold-start stutters, and improving overall fuel economy. Below, I’ll share my comprehensive analysis of the best spark plugs for Infiniti FX35, breaking down whether you need a full coil kit or just the plugs for a smooth, powerful ride across the model years.

IMAGE	PRODUCT NAME	AMAZON LINK
	UF550 Ignition Coil & 1406 Double Iridium Spark Plug for…	View on Amazon
	1406 Double Iridium Spark Plug for Infiniti EX35 FX35 G25…	View on Amazon
	ENA Set of 6 Iridium Spark Plug and 6 Ignition…	View on Amazon
	BDFHYK Set of 6 Iridium Spark Plug Compatible with…	View on Amazon
	Set of 6 Ignition Coil Pack and Spark Plugs fits…	View on Amazon
	AULINK UF550 C1670 Ignition Coil Spark Plug 6 PCS For…	View on Amazon
	HYR Set of 6 Ignition Coil Pack and Iridium Spark…	View on Amazon
	Iridium Spark Plugs 6 Pack 4469 LFR5AIX11 Fits for 2002…	View on Amazon
	AULINK UF401 Ignition Coil Pack 6PCS & 4469 Spark Plugs…	View on Amazon
	BDFHYK 6240 Iridium Spark Plugs Compatible with INFINITI…	View on Amazon

UF550 Ignition Coil & 1406 Double Iridium Spark Plug for Nissan Altima Maxima Murano Pathfinder Quest 350Z/Infiniti EX35 FX35 G25 G35 JX35 M35 M35h Q50 Q70 QX60 3.5L V6 C1670 22448-JA10C 5C1727

This combination kit is an excellent choice if your FX35 is experiencing misfires or poor idle quality, signaling worn plugs and aging coils. Not only do you get a full set of new ignition coils, but the included 1406 Double Iridium plugs ensure exceptional durability and performance, rated for a 100,000-kilometer lifespan. This setup is specifically tailored for the later model FX35 (2009-2012) running the revised VQ engine, providing a superior solution for engine maintenance.

Key features that stand out:
– Double Iridium Spark Plug: Offers extremely long service life (up to 100,000 kilometers).
– Superior Cold-Start Performance: Engineered to provide a consistent and stable spark immediately upon startup.
– Advanced Coil Design: Utilizes internal ferrite noise suppressor to prevent radio frequency interference (RFI).

Pros:
– Complete package (coils and plugs) provides a total ignition system refresh.
– High-quality materials designed to meet or exceed OE specifications.
– Long-term durability reduces maintenance frequency.

Cons:
– While installation is straightforward, replacing the coils adds complexity and time to the tune-up.

Best for: Comprehensive Ignition System Renewal for 2009-2012 Infiniti FX35 models.

Expert Opinion: If your FX35 has passed the 100,000-mile mark and you’ve never replaced the coils, this combination is the smartest investment to restore factory performance.

1406 Double Iridium Spark Plug for Infiniti EX35 FX35 G25 G35 JX35 M35 M35h M56 Q50 Q70 QX60/Nissan Altima Maxima Murano Quest 350Z V6 Replaces # DILKAR7B11 (Set of 6)

If your ignition coils are still in good shape, but you’re simply looking for the best performance spark plug replacement for your newer generation FX35 (2009-2012), the 1406 Double Iridium set is a fantastic option. These plugs are known for their exceptional ignitability, providing faster starts and noticeably quicker acceleration compared to standard platinum plugs. The use of double iridium ensures that they maintain this performance for a very long period, making them a true “set-it-and-forget-it” component.

Key features that stand out:
– Direct OE Replacement: Specifically replaces the original DILKAR7B11 plug.
– Iridium Center Electrode: Ensures rapid and reliable ignition, enhancing fuel economy.
– 100,000 Kilometer Lifespan: Offers superior longevity and consistent performance over time.

Pros:
– Excellent performance boost and reliability.
– Matches OE specifications perfectly for fitment and thermal range.
– Ideal for routine high-mileage maintenance.

Cons:
– This is a plug-only set, so if coils are failing, you’ll need to purchase them separately.

Best for: Performance-Focused Plug Replacement on 2009-2012 Infiniti FX35 models.

Expert Opinion: This is the preferred choice for enthusiasts who already have healthy coils but demand the longest-lasting, highest-quality double iridium plug available for their VQ engine.

ENA Set of 6 Iridium Spark Plug and 6 Ignition Coil Pack Compatible with Nissan Infiniti Maxima Murano Pathfinder Quest Altima Q50 QX60 FX35 3.5L V6 Replacement for UF550

ENA offers a cost-effective, full replacement solution that pairs Iridium spark plugs with new ignition coils, compatible with the later model FX35 (2009-2012). Engineered to operate reliably under all conditions, this set is designed for quick and easy installation, bringing your engine back up to factory standards. The included 24-Month Warranty provides significant peace of mind, especially when replacing critical components like the ignition system.

Key features that stand out:
– Complete Ignition Solution: Includes both UF550 replacement coils and Iridium spark plugs.
– Rigorous Engineering: Designed specifically to handle the demands of the VQ 3.5L engine.
– 24-Month Warranty: Provides assurance against premature failure of the components.

Pros:
– Highly competitive price point for a complete coil and plug kit.
– Improves rough idle and poor fuel economy often caused by aging coils.
– Direct plug-and-play installation based on OE design.

Cons:
– While the iridium plugs are excellent, they may not offer the extreme longevity of double iridium options.

Best for: Value-Driven Complete Tune-Up for 2009-2012 Infiniti FX35.

Expert Opinion: For the driver who needs to refresh the entire ignition system on a budget without sacrificing quality and coverage, ENA delivers a very solid package.

BDFHYK Set of 6 Iridium Spark Plug Compatible with INFINITI QX60 Q50 Q70 M35h JX35 EX35 FX35 G25 G35, Compatible with Nissan Maxima Murano Pathfinder Altima Quest 350Z,Replacement for 1406 DILKAR7B11

This BDFHYK set offers direct compatibility with the 1406/DILKAR7B11 plug, targeting Infiniti FX35 models from 2009 to 2012. These plugs feature extremely fine iridium electrodes that boost ignition performance, offering quicker and more sensitive ignition jumps. Manufactured in a TS16949 certified facility, the focus here is on achieving OE standard durability and performance using high-density ceramic insulators for reliable high-voltage output.

Key features that stand out:
– Fine Iridium Electrodes: Maximizes ignition performance and combustion efficiency.
– High-Quality Isostatic Ceramics: Ensures high density and superior insulation properties.
– Increased Power Performance: Claims to offer a noticeable improvement in engine response.

Pros:
– Strong focus on OE standard manufacturing and material quality.
– Excellent response time and reliable sparking.
– A trusted direct replacement for the newer VQ plugs.

Cons:
– Installation requires careful confirmation of the OE part number before purchase.

Best for: Reliable OE-Spec Iridium Performance in 2009-2012 FX35 V6 engines.

Expert Opinion: If you trust aftermarket OE replacements that adhere strictly to manufacturing standards, this BDFHYK set provides the durability and strong ignition required by the modern VQ engine.

Set of 6 Ignition Coil Pack and Spark Plugs fits for Infiniti FX35 G35 M35 Nissan 350Z 2003 2004 2005 2006 2007 2008 3.5 V6 Replaces# UF401 4469

This is the essential package for owners of the early generation FX35 (2003-2008). This kit combines UF401 replacement coils and 4469 spark plugs, covering the components specifically required by the VQ35DE engine used in those years. These coils are enhanced, claiming to upgrade 15% more energy than the original equipment, which can drastically improve performance if you’ve been dealing with sputtering or poor gas mileage.

Key features that stand out:
– Compatibility with Early Models: Perfect fitment for the 2003-2008 FX35.
– Enhanced Coil Energy: Provides potentially 15% more spark energy than OE for better combustion.
– Premium Materials: Uses highly conductive copper wire and high dielectric performance epoxy.

Pros:
– Specifically designed for the UF401/4469 early model VQ setup.
– Addresses both common failure points (coils and plugs) simultaneously.
– Reliable solution for resolving misfires and hesitation.

Cons:
– The 4469 plug type may not be as long-lasting as the double iridium options available for later models.

Best for: Complete Restoration of Early Model (2003-2008) FX35 Ignition System.

Expert Opinion: If you own an early FX35, ensure you are buying the UF401 coil kit. This package is optimized for that specific engine generation and offers a noticeable performance upgrade.

AULINK UF550 C1670 Ignition Coil Spark Plug 6 PCS For Infiniti EX35 FX35 G25 G35 JX35 M35 M35h Q50 Q70 QX60,Nissan 350Z Maxima Quest Pathfinder Murano Altima Xterra 3.5L V6

AULINK offers a high-quality replacement kit that is compatible with the 2009-2012 FX35. This setup utilizes impact and high-temperature-resistant ignition coils paired with trivalent metal plated spark plugs, ensuring excellent longevity and superior conductivity. The fact that these components are manufactured in TS16949 certified facilities emphasizes their commitment to quality and strict process control.

Key features that stand out:
– TS16949 Certified: Indicates manufacturing under stringent quality standards.
– Trivalent Metal Plating: Provides excellent anti-corrosion properties on the spark plugs.
– Wide OEM Cross-Reference: Ensures compatibility with a huge range of VQ 3.5L vehicles post-2007.

Pros:
– Comprehensive warranty coverage (1 Year or 50,000 km).
– Excellent temperature and impact resistance in the coil bodies.
– Thoroughly tested for function and leakage before leaving the factory.

Cons:
– The plugs included are not specifically detailed as double iridium, suggesting they are a high-quality standard iridium type.

Best for: Quality Assured OE Replacement for newer VQ engines.

Expert Opinion: A solid and reliable choice for a full system replacement. Their commitment to testing and certification makes them a trustworthy alternative to major brand names.

HYR Set of 6 Ignition Coil Pack and Iridium Spark Plugs Fit for 3.5L 2003-2008 Infiniti FX35 G35 M35 Nissan 350Z V6 Replaces UF401

Specifically tailored for the 2003-2008 FX35 VQ35DE engine, this HYR kit focuses on maximizing power and efficiency. The ignition coils are a standout feature, utilizing imported German copper wire to generate over 35,000 volts—significantly higher than standard OE outputs. This high-voltage spark results in more complete combustion, leading to improved fuel economy and better power delivery.

Key features that stand out:
– Ultra-High Voltage Coils: Capable of generating 35,000+ volts for complete combustion.
– Iridium Spark Plug Features: High-quality iridium electrodes solve cold start and idle shaking issues.
– Engineered for Early VQ: Correct replacement for UF401 coils and older OE plug numbers.

Pros:
– Noticeable improvement in acceleration and power delivery due to high-output coils.
– Effective at eliminating common cold-start and idling issues.
– Long-lasting wear resistance from the iridium plugs.

Cons:
– While powerful, some owners might prefer the standard OE voltage to avoid stressing other electrical components.

Best for: Early FX35 Owners Seeking Power and Efficiency Gains.

Expert Opinion: This is a strong performance upgrade for the first-generation FX35. The combination of high-output coils and quality iridium plugs is hard to beat for real-world driving benefits.

Iridium Spark Plugs 6 Pack 4469 LFR5AIX11 Fits for 2002 2003 2004 2005 2006 Nissan Altima 3.5 Maxima Murano Pathfinder Frontier Quest Xterra & Infiniti G35 FX35 M35 I35 V6 3.5L Spark Plug

If you own an FX35 manufactured between 2003 and 2008 and only require the spark plugs, this Iridium set is the right fit. Replacing the popular 4469/LFR5AIX-11 OE number, these plugs feature a tiny 0.6mm fine-wire iridium center tip, ensuring focused and efficient spark delivery. The iridium alloy provides exceptional durability against heat and electrical wear, making them ideal for today’s high-performance VQ engines.

Key features that stand out:
– 0.6mm Fine-Wire Tip: Focuses the spark for exceptional ignitability and fuel efficiency.
– Extreme Durability: Iridium alloy is six times harder than platinum, enhancing longevity.
– Comprehensive Compatibility: Correct fitment for the early FX35 VQ35DE engine.

Pros:
– Excellent choice for maximizing fuel efficiency and performance.
– High resistance to thermal and electrical wear ensures long life.
– A reliable alternative to OE plugs for early models.

Cons:
– The fine wire tip requires careful handling during installation to prevent damage.

Best for: Early Model FX35 Plug-Only Replacement focused on Efficiency.

Expert Opinion: For the 2003-2008 models, these plugs are a slight upgrade over standard platinum due to the fine-wire tip, providing cleaner combustion and better engine response.

AULINK UF401 Ignition Coil Pack 6PCS & 4469 Spark Plugs 3.5L For Nissan 350Z 2003-2006,for Infiniti FX35 2003-2008,G35 2003-2007,M35 2006-2008 C1439 IGC0007 2448AL61C 6734025 IGC153

This AULINK combination kit targets the specific ignition needs of the 2003-2008 Infiniti FX35. It bundles the correct UF401 coils and 4469 plugs into one package, simplifying the buying process. Just like their UF550 counterpart, these parts are manufactured in TS16949 certified facilities, emphasizing durability, high impact resistance, and rigorous testing standards, ensuring you get a reliable replacement for your VQ35DE.

Key features that stand out:
– Specific Early Model Fitment: Guaranteed to fit the 2003-2008 FX35 V6.
– High-Temperature Resistance: Coils are designed to withstand extreme engine bay heat.
– Quality Tested: Every unit is 100% tested for function and leakage.

Pros:
– Convenient all-in-one package for a complete tune-up.
– High manufacturing standards provide component reliability.
– Effectively cures misfire and rough idle symptoms.

Cons:
– The included 4469 plugs are high quality but not the longest lifespan option available on the market.

Best for: Reliable All-in-One Service Kit for 2003-2008 FX35.

Expert Opinion: If you are tackling a full tune-up on an older FX35, grabbing this kit prevents guesswork regarding compatibility and quality assurance.

BDFHYK 6240 Iridium Spark Plugs Compatible with INFINITI for Nissan FX35 FX45 G35 I35 M35 M45 Q45 QX4 QX56 350Z Altima Armada Frontier Maxima Murano Quest TITAN Xterra PLFR5A-11 Set of 6

The BDFHYK 6240 Iridium plugs are an excellent, high-performance option for the early VQ engines (2003-2008 FX35), replacing the popular PLFR5A-11 OE number. These plugs are engineered to maximize power and save energy consumption during the ignition process. Featuring extremely fine iridium electrodes and high-density ceramic insulators, they provide consistent, reliable performance crucial for the high demands of the 3.5L engine.

Key features that stand out:
– OE Part Number 6240 Replacement: A perfect match for many pre-2008 Infiniti VQ engines.
– Maximized Power Performance: Fine electrodes ensure sensitive and faster ignition jumps.
– Isostatic Ceramic Insulators: Guarantees superior insulation and physical strength under heat.

Pros:
– Strong focus on ignition responsiveness and reliability.
– High-quality construction built to OE standards.
– Ideal for routine replacement of standard factory plugs.

Cons:
– This plug may require checking the gap before installation, unlike some pre-gapped alternatives.

Best for: High-Performance Spark Plug Upgrade for 2003-2008 FX35.

Expert Opinion: The 6240 plugs are a recognized, quality standard in the aftermarket for the VQ engine series, offering excellent durability and ignition performance.

Comparison: Choosing the Best Spark Plugs For Infiniti FX35

When evaluating the best spark plugs for Infiniti FX35, the most crucial factor is your vehicle’s model year, as this dictates the correct coil and plug type (UF401/4469 for 2003-2008 vs. UF550/1406 for 2009-2012).

For owners of the 2003–2008 FX35 (UF401), you’ll be choosing between the standard Iridium 4469 replacements (like those from AULINK or BDFHYK 6240) and performance upgrades like the HYR high-output coil kit. If your priority is raw power and fixing sputtering, the HYR kit with its 35,000+ volt coils offers the most aggressive solution. If you only need plugs, the BDFHYK 6240 is a highly reliable OE standard replacement.

If you drive a 2009–2012 FX35 (UF550), you have access to superior double iridium technology. The UF550 Ignition Coil & 1406 Double Iridium kit is the top choice for maximum lifespan and peace of mind, rated for up to 100,000 kilometers. If your coils are healthy, buying the 1406 Double Iridium Plug-Only Set is the most cost-effective way to achieve long-term ignition reliability. The ENA and AULINK kits offer great value for a full refresh, pairing standard iridium plugs with new coils at a competitive price point.

Final Verdict on the Best Spark Plugs For Infiniti FX35

Deciding on the best spark plugs for Infiniti FX35 depends entirely on the age of your vehicle and the condition of your existing ignition coils.

Best Overall Longevity (2009-2012 Models):
The 1406 Double Iridium Spark Plug Set (plug-only) stands out. Double Iridium plugs offer the longest lifespan and maintain peak performance for tens of thousands of miles, minimizing future maintenance hassle.

Best Comprehensive Kit for Newer FX35 (2009-2012):
The UF550 Ignition Coil & 1406 Double Iridium Spark Plug combination is unbeatable for a full system overhaul. It solves all ignition concerns at once with premium, long-lasting components.

Best Value/Performance for Early FX35 (2003-2008):
The HYR Set of 6 Ignition Coil Pack and Iridium Spark Plugs is the winner here. The high-output coils provide a genuine performance bump over stock, which is highly beneficial for older VQ engines prone to power loss.

Best Spark Plugs For Infiniti FX35 FAQ

What are the signs that my Infiniti FX35 needs new spark plugs?

The most common signs are engine misfires (especially under hard acceleration), rough idling where the vehicle shakes slightly while stopped, difficulty starting (particularly in cold weather), poor acceleration response, and a noticeable drop in fuel economy (LSI keyword: poor gas mileage). If your check engine light is flashing, that often indicates a severe misfire.

How often should I replace the best spark plugs for Infiniti FX35?

For most Infiniti FX35 models, the factory-recommended interval for premium Iridium or Double Iridium plugs is typically between 60,000 and 105,000 miles. Always check your owner’s manual for the specific recommendation for your model year, but replacing them around the 80,000 to 100,000-mile mark is a safe practice to maintain peak performance.

Do I need to replace the ignition coils when I replace the spark plugs?

Not always, but it’s highly recommended, especially on higher-mileage vehicles (over 100,000 miles). Infiniti VQ engines are known for their reliability, but the coils eventually wear out. If you are replacing the plugs, it’s a good preventative measure to replace the coils at the same time, particularly the coils on the rear cylinder bank, as they are harder to access (LSI keyword: infiniti fx35 ignition coils).

What is the difference between Iridium and Double Iridium spark plugs?

Standard Iridium plugs use an iridium fine-wire tip on the center electrode. Double Iridium plugs add a platinum pad or iridium on the ground electrode as well. This makes the spark more consistent and significantly reduces electrode wear, resulting in a longer lifespan and more stable spark over time, perfect for modern VQ engines.

What spark plug gap should I use for my FX35?

The correct spark plug gap is absolutely critical for performance. For the 3.5L VQ engine in the FX35, the factory specification is typically 0.043 inches (1.1 mm). While many modern iridium plugs come pre-gapped, it is always essential to verify the gap using a wire-type gauge before installation, especially when installing aftermarket options.

Are the spark plugs the same for the early (2003-2008) and late (2009-2012) FX35 models?

No. The VQ engines used across the FX35 generations require different parts. Early models (2003-2008) typically use the UF401 coil and plugs replacing part number 4469 or PLFR5A-11. Later models (2009-2012) use the UF550 coil and plugs replacing part number DILKAR7B11. Using the wrong plug type can lead to poor performance or potential engine damage.