Best Spark Plugs For Lexus RX350

I recently tackled the spark plug replacement on my Lexus RX350, and honestly, picking the right set felt like a massive task. If you own an RX350 (especially the reliable 2007-2015 generation), you know how crucial smooth engine operation is. Getting the best spark plugs for your Lexus RX350 can directly impact your mileage, engine responsiveness, and cold starting ability. I’ve put together this comprehensive guide based on detailed comparisons of the top options available, so you can choose confidently and get back to enjoying that smooth V6 performance.

IMAGE	PRODUCT NAME	AMAZON LINK
	6 pc NGK Iridium IX Spark Plugs compatible with Lexus…	View on Amazon
	6 pc DENSO Iridium Power Spark Plugs compatible with…	View on Amazon
	NGK 6619 Iridium Spark Plugs LFR6AIX-11-6 PCSNEW	View on Amazon
	6 pc DENSO Iridium TT Spark Plugs compatible with Lexus…	View on Amazon
	6 pc Autolite Platinum Spark Plugs compatible with Lexus…	View on Amazon
	Ignition Coil Pack Spark Plugs Replacement for 3.5 V6…	View on Amazon
	BDFHYK Ignition Coil Pack UF487 and Iridium Spark Plug…	View on Amazon

6 pc NGK Iridium IX Spark Plugs compatible with Lexus RX350 3.5L V6 2007-2015

NGK is often the benchmark when it comes to ignition components, and the Iridium IX series is specifically designed for enthusiasts who demand strong performance paired with excellent longevity. When I put these in, I immediately noticed a slight improvement in throttle response compared to the old plugs. This is a reliable, genuine NGK replacement that ensures your 3.5L V6 maintains its original factory specifications for power and efficiency. If you are looking for a true OEM-quality plug upgrade without sacrificing durability, this is a fantastic choice.

Key features that stand out:

• Genuine Parts: Guaranteed genuine NGK components in original packaging.
• Direct Replacement: Engineered specifically for the Lexus RX350 3.5L V6 (2007-2015).
• Iridium Tip: Provides superior durability and a consistently strong, concentrated spark.

Pros:
– Known for exceptional long-term reliability and reduced misfires.
– Excellent cold-starting capabilities.
– Considered an industry standard for Japanese performance vehicles.

Cons:
– Iridium IX plugs are slightly more expensive than standard Platinum options.

Best for:
Drivers seeking genuine, high-performance reliability that meets or exceeds OEM specifications.

Expert Opinion: NGK Iridium IX plugs are celebrated for their thin wire center electrode, which requires less voltage to fire. This translates directly to a more complete combustion cycle in your RX350 engine, improving low-end torque and ensuring smooth idling.

6 pc DENSO Iridium Power Spark Plugs compatible with Lexus RX350 3.5L V6 2007-2015

DENSO is another trusted name that supplies many Japanese manufacturers, including Lexus, with OEM parts. The Iridium Power series is designed with performance in mind. Featuring an incredibly thin 0.4mm iridium tip, these plugs deliver a larger, more focused spark, which can lead to noticeable gains in both power and superior fuel economy. If you want to maximize the efficiency of your Lexus 3.5L V6, these are built to handle high temperatures and deliver maximum spark energy consistently.

Key features that stand out:

• Ultra-Fine Iridium Tip: Features a 0.4mm iridium tip for concentrated, powerful sparking.
• Performance Focus: Designed for maximum performance and power sports applications.
• Durability: Able to withstand temperatures greater than 4000 degrees Fahrenheit.

Pros:
– Proven to offer better acceleration and quicker throttle response due to the fine tip.
– Excellent heat resistance prevents premature plug wear.
– Direct OE fitment guarantees compatibility with the RX350.

Cons:
– The emphasis on performance means the service life might be slightly shorter than some ultra-long-life plugs.

Best for:
Drivers prioritizing engine response and maximizing horsepower output from their RX350.

Expert Opinion: The unique tapered cut and U-Groove ground electrode featured in the DENSO Iridium Power plugs ensure that the spark kernel has minimal quenching effect, allowing it to expand quickly. This technology provides a significantly more robust burn across various operating conditions.

NGK 6619 Iridium Spark Plugs LFR6AIX-11-6 PCSNEW

The NGK 6619 (LFR6AIX-11) is a specific part number that aligns perfectly with the requirements of the Lexus RX350 engine. These are premium Iridium plugs designed to operate effectively across a much wider heat range than traditional copper or nickel plugs. This ability helps resist issues like carbon buildup during city driving and pre-ignition when the engine is pushed hard. Their patented triple gasket sealing process also eliminates the worry of combustion gas leakage, ensuring all the engine’s power is properly utilized.

Key features that stand out:

• Wide Heat Range: Operates efficiently under varied engine stresses, resisting both fouling and overheating.
• Triple Gasket Seal: Patented sealing process ensures no combustion gas leaks.
• Resistance: Built to resist carbon buildup and dangerous pre-ignition.

Pros:
– Excellent choice for reliable, consistent performance in varied climates.
– Long lifespan reduces the frequency of plug changes.
– Specific OEM replacement number ensures a hassle-free fit.

Cons:
– Appearance and packaging might look less exciting than some of the newer performance lines.

Best for:
The driver seeking a proven, standard-bearer iridium plug with excellent anti-fouling characteristics for everyday reliability.

Expert Opinion: The 6619 is a workhorse plug within the NGK lineup. Its strength lies in its consistency and its ability to handle the typical stop-and-go driving cycles common in SUV use while still providing solid highway performance.

6 pc DENSO Iridium TT Spark Plugs compatible with Lexus RX350 3.5L V6 2007-2015

The DENSO Iridium TT (Twin Tip) technology represents a leap forward in spark plug design. Unlike standard plugs, these feature a fine 1.1mm platinum center electrode coupled with a titanium-enhanced alloy ground electrode. This twin-tip design enables maximum spark energy, making them incredibly effective at handling extreme compression and boost levels (though typically stock on an RX350, this speaks to their durability). What you get in your RX350 is highly efficient combustion, translating to maximized fuel efficiency and responsive power delivery.

Key features that stand out:

• Twin-Tip (TT) Design: Provides the highest concentration of spark for efficient combustion.
• Enhanced Durability: Features a titanium-enhanced ground electrode for superior resilience.
• Efficiency Focus: Optimized for better fuel economy while maintaining high power output.

Pros:
– Among the longest-lasting plugs available due to the TT technology.
– Highly resistant to fouling and misfires even under heavy load.
– Noticeable improvement in idling smoothness reported by many users.

Cons:
– Often priced at the high end of the replacement plug market.

Best for:
Drivers prioritizing maximum fuel efficiency and the absolute longest service life possible from a spark plug.

Expert Opinion: The Iridium TT line is essentially DENSO’s long-life flagship product. By using two tiny, projecting electrodes, they ensure the spark is less shielded by the plug body, resulting in a cleaner and more effective burn in the combustion chamber.

6 pc Autolite Platinum Spark Plugs compatible with Lexus RX350 2007-2019

If you’re looking for a dependable, cost-effective replacement that still offers a significant upgrade over basic plugs, the Autolite Platinum series is a great option. These plugs use a platinum-to-platinum firing design for superior durability and virtually no gap erosion, ensuring a long, consistent life. They are compatible with a slightly wider range of model years (up to 2019) than some competitors. The Yttrium enhanced ground electrode aids in superior heat transfer, helping the engine start quicker and accelerate smoothly.

Key features that stand out:

• Platinum-to-Platinum Firing: Ensures excellent gap stability over time for longer life.
• Yttrium Enhanced Electrode: Provides excellent heat transfer and durability.
• Wide Compatibility: Fits Lexus RX350 models from 2007 all the way to 2019.

Pros:
– Excellent balance of price and longevity (a great value option).
– Platinum materials offer much better resistance to fouling than copper.
– Designed for easier starts and quicker acceleration compared to older plug types.

Cons:
– Platinum typically doesn’t offer the same performance kick as high-end Iridium plugs.

Best for:
Budget-conscious owners looking for a reliable, long-life plug that offers better performance than basic OEM replacements.

Expert Opinion: Autolite Platinum plugs are designed to be a significant upgrade for vehicles that originally used standard nickel or copper plugs. For the RX350, they provide reliable performance and superior durability for those who might not need the extreme longevity of Iridium.

Ignition Coil Pack Spark Plugs Replacement for 3.5 V6 Toyota Sienna Avalon Camry Highlander Rav4 Venza Lexus RX350 ES350 RX450h 2007 2008 2009 2010 2011 2012 2013 2014 2015, 90919-A2007, UF487, 6pc

This package is different: it’s a 6-piece combo kit that includes both the spark plugs and the ignition coils (UF487). While the brand isn’t named (often a generic aftermarket supplier), the benefit here is convenience. If your RX350 is showing symptoms of both failing coils (like rough idle or engine misfire) and old plugs, this kit allows you to refresh the entire ignition system in one go. The parts are designed to meet or exceed OEM specifications for the 3.5L V6 engine family used across Lexus and Toyota vehicles.

Key features that stand out:

• Complete Ignition Refresh: Includes 6 coils and 6 pre-gapped spark plugs.
• Troubleshooting Solution: Ideal for solving issues like engine misfire, hard starts, and rough idling simultaneously.
• Wide Fitment: Compatible with a large range of Toyota/Lexus 3.5L V6 engines (Camry, Highlander, ES350, etc.).

Pros:
– Highly convenient and often saves money compared to buying coils and plugs separately.
– Solves multiple ignition problems in a single service appointment.
– Coils are direct replacements for OEM part number UF487.

Cons:
– Quality control on generic aftermarket coils and plugs can sometimes be less consistent than brand-name components.

Best for:
Owners who need to replace both their coils and plugs immediately to resolve a persistent misfire issue.

Expert Opinion: When replacing spark plugs on older Lexus V6 engines, coils should always be inspected. If your vehicle is over 100,000 miles, purchasing a combo kit like this offers peace of mind, provided you accept the risks associated with non-OEM coil quality.

BDFHYK Ignition Coil Pack UF487 and Iridium Spark Plug 6619 Compatible with Lexus ES350 2007-2015 Lexus RX350 Toyota RAV4 Avalon Camry Toyota Sienna Toyota Coil Pack Coil for Lexus 3.5L Set of 6

Similar to the previous entry, this is a complete ignition package, but this time, it specifically names the components: the well-regarded Iridium Spark Plug 6619 (an NGK part number) and the UF487 coil. This kit aims to provide the best of both worlds—the convenience of a full replacement set combined with high-quality Iridium materials for the spark plugs. The coils are advertised as being made with quality materials like silicon steel and Japan-imported rubber for durability.

Key features that stand out:

• Quality Components: Pairs a reliable UF487 coil pack with the premium Iridium 6619 spark plug.
• Comprehensive Refresh: Ideal for cars exceeding 80,000 km showing signs of degradation (shaking, slow acceleration).
• Durable Coil Construction: Coils utilize silicon steel and high-quality rubber for long life.

Pros:
– Eliminates guesswork by pairing a proven spark plug (6619) with the necessary coil pack.
– Excellent solution for resolving common high-mileage ignition problems.
– Better confidence in spark plug quality compared to fully generic combo kits.

Cons:
– While the plug is high quality, the longevity of the generic coils is still a minor concern for some buyers.

Best for:
RX350 owners with high mileage who specifically want Iridium plugs but also need to refresh their ignition coils due to age or wear.

Expert Opinion: This specific kit is often favored because it includes the known, high-quality Iridium 6619 plug. By addressing both the plug and the coil, the kit ensures the entire ignition path is refreshed, restoring “new car” performance and responsiveness.

Spark Plug Comparison Short Insights

When looking at the Best Spark Plugs For Lexus RX350, the decision often comes down to budget versus expected lifespan and performance.

The NGK Iridium IX and DENSO Iridium Power are the gold standards. They are premium plugs that offer noticeable performance gains and fantastic durability. If your budget allows, investing in one of these two brands will give you the longest replacement interval and the smoothest engine operation.

If you are focused purely on longevity and maximizing fuel economy, the DENSO Iridium TT takes the lead with its advanced twin-tip design. This plug is engineered to provide the cleanest spark over the longest period.

For the value seeker, Autolite Platinum is a very strong contender. While it might not match the 120,000+ mile intervals of some Iridium plugs, its platinum construction provides long, reliable service life at a much more accessible price point than the high-end Iridium options.

Finally, the combination kits (Ignition Coil Pack/Spark Plug sets) are a convenience play. If your RX350 is experiencing consistent misfires or stumbling, it’s highly probable the coils are failing alongside the plugs. Choosing a kit like the BDFHYK which pairs the coils with the specified Iridium 6619 plug is a smart, time-saving solution, even if the coils themselves aren’t OE Toyota/Lexus parts.

Final Verdict: Choosing the Right Spark Plug

Making the right choice depends on what you value most in your Lexus RX350.

The All-Around Reliability Champion: For most RX350 owners seeking the best balance of longevity, performance, and compatibility, we confidently recommend the 6 pc NGK Iridium IX Spark Plugs compatible with Lexus RX350 3.5L V6 2007-2015. NGK is synonymous with quality, and this plug delivers consistent, worry-free performance for years.

The Mileage Maximizer: If achieving the best possible fuel economy and the absolute longest service life is your top priority, you should choose the 6 pc DENSO Iridium TT Spark Plugs compatible with Lexus RX350 3.5L V6 2007-2015. The advanced twin-tip technology provides superior combustion efficiency.

The Budget-Conscious Performance Upgrade: For an owner who needs a reliable, long-life replacement without the high price tag of ultra-premium Iridium, the 6 pc Autolite Platinum Spark Plugs offer excellent value and consistent results, especially with their broader year compatibility.

FAQs About the Best Spark Plugs for a Lexus RX350

Q1: When should I change the spark plugs in my Lexus RX350 3.5L V6?

The recommended replacement interval for factory Iridium spark plugs in the Lexus RX350 (2007-2015) is typically every 90,000 to 120,000 miles. However, if you use a high-performance Iridium plug (like DENSO Iridium Power) or a Platinum plug (like Autolite), it’s wise to check them closer to the 60,000 to 80,000-mile mark, especially if you notice a decrease in RX350 fuel economy or engine smoothness.

Q2: Is Iridium really better than Platinum for the Lexus RX350 engine?

Yes, generally, Iridium is superior. Iridium is harder and melts at a much higher temperature than platinum. This allows Iridium plugs to use thinner center electrodes (like 0.4mm in the DENSO Iridium Power), which requires less voltage to create a spark. This results in more efficient combustion, better cold starts, and a significantly longer lifespan—often 50% longer than comparable platinum plugs.

Q3: What symptoms indicate I need new spark plugs in my RX350?

The most common signs of failing spark plugs include a noticeable engine misfire (a shuddering or skipping feeling, especially under acceleration), difficulty starting the vehicle, rough or uneven idling, and a marked decrease in Lexus RX350 performance and fuel efficiency. If your check engine light is flashing, it often signals a severe misfire.

Q4: Do I need to gap the Iridium spark plugs before installing them in my Lexus RX350?

While premium Iridium spark plugs like NGK and DENSO are usually pre-gapped correctly from the factory for your specific application, it’s always best practice to confirm the gap using a wire-style feeler gauge. The correct Lexus RX350 spark plug gap specification should be checked against your owner’s manual or a reliable repair guide. Never use a coin-style gap tool on fine-wire Iridium tips, as it can damage the electrode.

Q5: Since I have to change my plugs, should I also replace the ignition coils on my high-mileage RX350?

For RX350 models exceeding 100,000 miles, it’s often highly recommended to replace the coils alongside the spark plugs. The Lexus RX350 ignition coils degrade over time, leading to misfires. Since accessing the rear bank of plugs and coils is labor-intensive, replacing both at the same time (using a combo kit or separate high-quality parts) saves future labor costs and ensures your entire ignition system is refreshed.

Q6: Why are spark plugs so critical for the smooth running of the 3.5L V6 engine?

The 3.5L V6 (2GR-FE) engine found in the RX350 is known for its refinement and balance. A high-quality spark plug ensures the air-fuel mixture ignites completely and consistently across all six cylinders. If one plug fails or provides a weak spark, the cylinder misfires, causing the engine management system to adjust, leading to noticeable vibrations, poor throttle response, and negatively affecting the famous RX350 smooth driving experience.