Best Spark Plugs For 350Z – 7 Options Reviewed

I’ve spent a lot of time wrenching on the iconic Z33 chassis, and I know how sensitive that VQ engine can be. When it comes to maintaining that signature V6 performance, ignoring the ignition system just isn’t an option. Choosing the best spark plugs for 350Z isn’t just about avoiding misfires; it’s about maximizing throttle response and maintaining fuel efficiency, especially if you have an older VQ35DE engine or the high-revving VQ35HR. We’ve broken down seven top-rated options, ranging from reliable OEM replacements to high-performance iridium choices, so you can make the right choice for your Zed.

IMAGE	PRODUCT NAME	AMAZON LINK
	6 pc NGK Iridium IX Spark Plugs compatible with Nissan…	View on Amazon
	NGK 4469 Iridium IX Spark Plugs LFR5AIX11 (6 Pack)	View on Amazon
	6 Pack 4469 LFR5AIX-11 Spark Plugs Iridium IX Fit for…	View on Amazon
	1406 Double Iridium Spark Plug for Infiniti EX35 FX35 G25…	View on Amazon
	A-Premium Iridium Platinum Spark Plugs 93501 LKAR7BIX-11S…	View on Amazon
	A-Premium (Red) Set of 12 Ignition Coil Pack and Iridium…	View on Amazon
	6 pc NGK V-Power Spark Plugs compatible with Nissan 350Z…	View on Amazon

6 pc NGK Iridium IX Spark Plugs compatible with Nissan 350Z 3.5L V6 2003-2006

This 6-piece NGK Iridium IX set is a fantastic choice for the earlier model 350Z (2003-2006 VQ35DE). NGK is often considered the gold standard for Nissan ignition components, and the Iridium IX line offers a substantial performance upgrade over traditional copper plugs. They provide excellent longevity and ensure a consistent, powerful spark critical for maintaining smooth idling and quick acceleration in a stock or lightly modified Z.

Key features that stand out:
– Genuine NGK Parts: Assurance of quality and fitment.
– Direct Replacement: Designed specifically for the 2003-2006 3.5L V6.
– Iridium Construction: Offers superior durability and lifespan compared to standard copper or platinum.

Pros:
– Excellent OE fitment and reliability for VQ35DE models.
– Improved throttle response due to the fine wire electrode.
– Recognized quality brand used by performance enthusiasts.

Cons:
– While durable, they don’t offer the extreme mileage life of some double iridium options.

Best for:
Daily driven 2003-2006 350Z owners seeking reliability and slightly improved performance without major modification.

Expert Opinion: For the VQ35DE engine, these NGK Iridium IX plugs are frequently recommended by mechanics. They provide the perfect balance between cost, performance, and replacement interval, ensuring the motor stays happy.

NGK 4469 Iridium IX Spark Plugs LFR5AIX11 (6 Pack)

The NGK 4469 (LFR5AIX11) is a globally popular specification for various Nissan and Infiniti VQ engines, including the 350Z. These plugs offer an extreme performance upgrade thanks to the specialized construction, which is highly resistant to fouling. Designed specifically for optimal engine and torque delivery, they feature a fine-wire Iridium center electrode for exceptional ignitability, ensuring faster starts and smoother operation across the power band.

Key features that stand out:
– Extreme Performance Upgrade: Built to handle demanding conditions.
– Iridium Center Electrode: Maximizes engine efficiency and torque delivery.
– Precision Laser Construction: Ensures consistent quality and gap maintenance.

Pros:
– Rated for a lifetime of 40,000 to 50,000 miles.
– Excellent performance for both naturally aspirated and mild turbo/supercharged applications.
– Highly resistant to heat damage.

Cons:
– They might be overkill if your Z is solely a weekend cruiser with low mileage.

Best for:
Performance-minded 350Z drivers who push their engines and require reliable ignition under stress.

Expert Opinion: The 4469 is a benchmark plug. We often see these installed when owners want to ensure they get reliable power output while extending their maintenance interval beyond traditional copper plugs.

6 Pack 4469 LFR5AIX-11 Spark Plugs Iridium IX Fit for 350Z 2003-2006, Altima 2002-2006, FJ Cruiser 2013-2014, Xterra 2005-2015, 3.5L 4.0L, Hyundai Nissan Infiniti Yamaha Spark Plug LFR5AIX11 LFR5AIX

This generic 6-pack offers the specific 4469 LFR5AIX-11 specification widely used in the early VQ35DE engine (2003-2006 350Z). While not branded NGK, these plugs match the critical technical specifications, including the 1.1mm gap size and 40K-50K kilometre life expectancy, making them an excellent budget-friendly replacement. The inclusion of a one-year warranty provides peace of mind, ensuring reliability even at a lower price point.

Key features that stand out:
– Matching OEM Specifications: Features the critical LFR5AIX11 specification.
– Generous Warranty: Backed by a one-year warranty against normal use issues.
– Iridium Core Material: Provides good conductivity and durability.

Pros:
– Highly cost-effective option for routine maintenance.
– Exact fitment for the popular 2003-2006 350Z application.
– Known life expectancy ensures reliable planning.

Cons:
– Brand reputation may not be as high as NGK, requiring careful pre-installation inspection.

Best for:
Budget-conscious owners of 2003-2006 350Z models performing routine maintenance who prioritize cost savings.

Expert Opinion: If budget is the primary driver, these offer the correct Iridium specification. However, always double-check the electrode gap upon arrival, as non-OEM plugs sometimes require minor adjustment.

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)

This set of Double Iridium plugs targets the later 350Z models equipped with the VQ35HR engine (2007-2009). Double Iridium technology offers exceptional longevity, designed to work up to 100,000 kilometers while providing a consistent and stable spark. If your 350Z is experiencing weak acceleration or rough idling, these high-quality replacement plugs can restore superior cold-start performance and engine smoothness.

Key features that stand out:
– Double Iridium Technology: Center and ground electrodes are Iridium for maximum lifespan.
– Exceptional Longevity: Designed to last significantly longer than single Iridium or platinum plugs (up to 100,000 km).
– OE Design Improvement: Ensures fast installation and reliable long-term performance.

Pros:
– Dramatically extended service life means less frequent replacement.
– Ideal specification (DILKAR7B11) for the VQ35HR engine.
– Improves fuel economy and reduces emissions.

Cons:
– These are specific to the later HR engine models and won’t fit the earlier DE engines.

Best for:
2007-2009 350Z owners who want a true long-life, OE-level ignition component upgrade.

Expert Opinion: Double Iridium is the technology of choice for modern factory long-life plugs. The difference in ignition stability, especially at higher mileage, makes these a worthwhile investment for the higher-revving VQ35HR.

A-Premium Iridium Platinum Spark Plugs 93501 LKAR7BIX-11S (Pack of 6) Compatible with Nissan Altima 2007-2018, Murano 2009-2020, Pathfinder, Maxima, Quest, 350Z & Infiniti QX60, Q50, G25, G35, M35

A-Premium offers a strong alternative for the later VQ35HR (2007-2009) engines with this Iridium Platinum hybrid set. By combining an Iridium tip center electrode with a Platinum core material, these plugs are engineered specifically for high mileage and longevity, often lasting 80,000 to 100,000 miles. They deliver stable performance, which is vital for maintaining the complex electronics and emissions controls of modern Z cars.

Key features that stand out:
– Iridium/Platinum Hybrid: Optimized material composition for maximum wear resistance.
– Extended Service Interval: Recommended replacement at 80,000 to 100,000 miles.
– Specific Fitment for HR Engines: Matches the critical LKAR7BIX-11S specification.

Pros:
– Designed for extreme long-term use and maximum reliability.
– Stable resistance characteristics (5000 ohms).
– Direct fit replacement for the 2007-2009 350Z.

Cons:
– The initial cost is higher than copper or single-platinum plugs, offset by the longevity.

Best for:
Owners of 2007-2009 VQ35HR 350Z models seeking “install and forget” longevity plugs.

Expert Opinion: These Iridium Platinum plugs are excellent if you want to align your spark plug changes with other major maintenance milestones, given their impressive lifespan rating. They provide highly stable ignition throughout their service life.

A-Premium (Red) Set of 12 Ignition Coil Pack and Iridium Spark Plugs Compatible with Nissan 350Z 2003-2006 & Infiniti FX35 2003-2008, G35 2003-2007, M35 2006-2008, 3.5L

If your 2003-2006 350Z is suffering from high mileage (over 100,000 miles) and displaying sluggishness or persistent misfires, replacing the entire ignition system might be necessary. This comprehensive kit includes six Iridium spark plugs and six matching ignition coils, all designed for the VQ35DE engine. The iridium plugs paired with new, high-quality coils ensure a complete system refresh, stabilizing idle speed, improving fuel efficiency, and reducing emissions significantly.

Key features that stand out:
– Complete Ignition Overhaul: Includes 6 coils (UF-401) and 6 Iridium plugs.
– Improved Stability: Ensures a more stable idle speed and faster starting.
– Iridium Spark Plug Material: Extends plug life nearly threefold compared to standard plugs.

Pros:
– Fantastic value when replacing coils and plugs simultaneously.
– Restores factory-fresh ignition performance immediately.
– One-year unlimited-mileage guarantee for peace of mind.

Cons:
– Coil replacement might be unnecessary if your existing coils are still functioning perfectly.

Best for:
High-mileage 2003-2006 350Z owners experiencing multiple misfire codes or overall ignition degradation.

Expert Opinion: Replacing just the plugs on a high-mileage Z is often a half-measure. We strongly recommend a complete coil/plug refresh like this kit if the car’s mileage is high and you’re chasing down persistent VQ ignition issues.

6 pc NGK V-Power Spark Plugs compatible with Nissan 350Z 3.5L V6 2003-2006

The NGK V-Power plugs (Copper) represent the traditional, reliable, and highly affordable option for the early VQ35DE motor. While they require more frequent replacement (typically every 20,000 to 30,000 miles), copper offers the best conductivity and a powerful spark, making them surprisingly popular with enthusiasts. They are a direct replacement and maintain the famous NGK quality, ensuring your Z runs smoothly without the premium cost of iridium.

Key features that stand out:
– V-Power Design: Features a unique V-groove center electrode for improved ignitability.
– Genuine NGK Quality: Guaranteed fitment and reliability for 2003-2006 350Z.
– Copper Core: Provides excellent conductivity for a powerful spark.

Pros:
– Lowest cost option for routine maintenance.
– Highly effective for stock or forced induction applications that require a colder, frequently changed plug.
– Very reliable and proven technology.

Cons:
– Requires the most frequent replacement compared to platinum or iridium plugs.

Best for:
350Z owners on a strict budget, or those with highly modified/boosted engines who need to change plugs often.

Expert Opinion: Don’t underestimate copper. If you don’t mind changing your plugs every other oil change (or slightly longer), the conductivity of copper is still superior for raw spark power, which is why racers still use them.

Comparison Insights: Which 350Z Spark Plugs Are Right For You?

Choosing the right plug often comes down to balancing cost, engine modification level, and how often you want to perform maintenance.

For VQ35DE (2003-2006) owners, NGK provides two great material choices: The NGK Iridium IX 4469 offers great performance and a 40k-50k mile interval, while the NGK V-Power copper plugs are the best budget choice but need changing every 20k-30k miles. If your DE model is showing signs of ignition system fatigue, the A-Premium coil and plug kit is highly recommended for a full refresh.

For VQ35HR (2007-2009) owners, the focus shifts entirely to longevity due to the plug’s difficult location and the engine’s design. Both the 1406 Double Iridium and the A-Premium Iridium Platinum options are engineered for the HR engine and promise maintenance intervals exceeding 80,000 miles, making them ideal long-term investments.

If you drive hard or track your Z, sticking to premium iridium specifications is usually the safest bet, as they handle heat much better than copper over long periods.

Final Verdict

Making the final decision on the best spark plugs for your 350Z depends entirely on your specific model year and performance goals.

For the VQ35DE (2003–2006 Daily Driver): Go with the 6 pc NGK Iridium IX Spark Plugs compatible with Nissan 350Z 3.5L V6 2003-2006. They are the perfect blend of OEM quality, lifespan, and performance for the early VQ.

For the VQ35HR (2007–2009 Longevity King): Your best investment is the 1406 Double Iridium Spark Plug. The VQ35HR plugs are tougher to access, making the 100,000 km lifespan of double iridium plugs extremely valuable.

For the High-Mileage/Budget Refresh: If you have an older Z suffering from misfires, skip replacing just the plugs and invest in the A-Premium Set of 12 Ignition Coil Pack and Iridium Spark Plugs. A full system refresh will solve persistent problems instantly and reliably.

Best Spark Plugs For 350Z – Comprehensive FAQ

What are the symptoms of bad spark plugs in a Nissan 350Z?

Common symptoms of failing spark plugs include the engine idling roughly, noticeable hesitation or stuttering during acceleration, reduced fuel economy, and difficulty starting the car. In severe cases, the “Check Engine Light” may illuminate, showing a misfire code (P0300 series). Replacing the best spark plugs for 350Z according to schedule prevents these issues.

What is the recommended spark plug change interval for the 350Z?

The recommended interval depends heavily on the plug material and engine type. For the earlier VQ35DE using standard copper V-Power plugs, change them every 20,000 to 30,000 miles. For high-quality Iridium spark plugs (like those used in the VQ35HR), the factory-recommended interval is often between 80,000 and 100,000 miles. Always check your owner’s manual or the plug manufacturer’s recommendation.

Is it necessary to replace the ignition coils when replacing the spark plugs?

It is not strictly necessary to replace the ignition coils every time, especially on lower mileage cars. However, if your 350Z (especially the VQ35DE models) has over 100,000 miles, replacing the coils along with the spark plugs is highly recommended. The coils degrade over time and can lead to misfires, even if the plugs are new. Look at complete ignition kits like the A-Premium option.

What is the difference between iridium and copper plugs for the VQ35?

Copper plugs (like NGK V-Power) offer superior electrical conductivity, providing a strong spark, which makes them great for performance applications that require frequent changes. Iridium spark plugs (like NGK Iridium IX) are much harder and more durable, offering significantly extended lifespan and better performance over a longer maintenance interval, making them ideal for daily drivers and long-life VQ35HR engines.

Do I need to gap my new spark plugs for the 350Z?

While high-quality, pre-gapped plugs (especially NGK) are usually ready to install, it is always best practice to check the gap size before installation, particularly with aftermarket or non-OEM brands. The specific gap size varies depending on your 350Z’s engine model (VQ35DE typically uses 0.044 inches, while the VQ35HR uses slightly different specifications).

Are the spark plugs different for the 2003-2006 VQ35DE versus the 2007-2009 VQ35HR?

Yes, the spark plugs are fundamentally different. The early VQ35DE engine uses a specific plug type (often LFR5AIX-11) that differs in thread pitch and reach from the plugs required by the later VQ35HR engine (often DILKAR7B11). Always confirm the exact part number for your specific model year to ensure proper fitment and performance.