A Lexus Mechanic's Guide to Spark Plugs for the 2007-2020 GS350
Keep your GS350's V6 engine running smoothly by choosing the right spark plugs and avoiding common mistakes.
- Stick with OEM-equivalent brands Denso or NGK for guaranteed performance and reliability.
- The 60,000-mile replacement interval is conservative; many owners wait until 100,000 miles or more if the engine runs well.
- This is a very feasible DIY project that can save you hundreds of dollars in labor.
- Verify the correct part number for your specific model year, as it differs between the 3rd and 4th generations.
Symptoms of Failing Spark Plugs in a GS350
When your spark plugs start to wear out, your GS350's engine performance will suffer. You might not get a Check Engine Light at first, but the signs will be there. Look out for these common symptoms:
- Rough Idle: The engine may shake or vibrate more than usual when you're stopped at a light.
- Hesitation on Acceleration: When you press the gas, the car may stumble or hesitate before picking up speed.
- Reduced Fuel Economy: You'll notice you're filling up the tank more often than you used to.
- Engine Misfires: This is a more serious symptom where a cylinder fails to ignite properly. It can feel like a shudder or a jerking motion while driving. This will usually trigger a Check Engine Light with codes like P0300 (random misfire) or P0301-P0306 (for a specific cylinder). 🎬 Learn how to diagnose engine misfires by inspecting your plugs.
- Difficulty Starting: The engine may take longer to crank over before it starts.
Choosing the Right Aftermarket Spark Plug
For the Lexus GS350, this is straightforward. The original equipment (OEM) manufacturers, Denso and NGK, are the best and most reliable choices. They are engineered specifically for your vehicle's ignition system. Using other brands can sometimes lead to performance issues.
Tier 1: OEM Equivalent
Denso & NGK: Both Denso and NGK are Japanese brands that supply spark plugs directly to Toyota/Lexus for factory installation. Choosing an Iridium plug from either of these brands is the safest bet for maintaining factory performance and longevity. They offer excellent durability and a stable spark. Many owners report going well over 100,000 miles on the original set.
Tier 2: Standard Aftermarket
Bosch, Autolite, Champion: These brands offer iridium and platinum plugs that will fit your GS350. While they are reputable brands for many vehicles, the overwhelming consensus among Lexus enthusiasts is to stick with the OEM suppliers (Denso/NGK) for best results. While a Bosch Iridium plug is a quality part, it may not offer the same exact performance characteristics the GS350's engine was designed for.
| Brand | Tier | Common Material | Notes |
|---|---|---|---|
| Denso | 1 (OEM) | Iridium | Factory supplier for Lexus. Highly recommended for performance and longevity. |
| NGK | 1 (OEM) | Iridium | Factory supplier for Lexus. Considered equal to Denso in quality and reliability. |
| Bosch | 2 | Iridium/Platinum | A quality alternative, but not the original equipment brand for this vehicle. |
| Autolite | 2 | Iridium/Platinum | Another functional alternative, though less commonly used by GS350 owners. |
| Champion | 2 | Iridium/Copper | Available, but Iridium is recommended over copper for this engine. |
Known Issues, Recalls, or TSBs
There are no specific recalls or Technical Service Bulletins (TSBs) from Lexus for spark plug failure on the 2007-2020 GS350. However, there have been recalls for fuel system components, such as fuel pumps and fuel delivery pipes, on some model years. Symptoms of these issues, like engine stalling, could potentially be confused with a severe ignition problem, so it's wise to check your vehicle's VIN for any open recalls.
Frequently Asked Questions (FAQ)
When should I actually replace the spark plugs? The dealer says 60,000 miles.
The official maintenance schedule often calls for replacement at 60,000 miles. This is generally considered a conservative interval, possibly to ensure the emissions system warranty remains valid. Many owners find the original iridium plugs are still in good condition at 60,000 miles and wait until 100,000-120,000 miles to replace them without any issues. If your car is running smoothly, extending the interval is common practice.
Is replacing the spark plugs on a GS350 a DIY job?
Yes, for a moderately skilled person, this is a very manageable DIY job that can save you hundreds of dollars in labor costs. The passenger side (Bank 1) is easily accessible. The driver's side (Bank 2) requires removing the air intake housing to access the ignition coils and plugs, but this is a straightforward process shown in many online videos. The entire job typically takes 1-2 hours.
🎬 Watch this step-by-step guide to changing your GS350 spark plugs.Why is the dealership quote so high?
Dealerships and some shops charge a high labor rate. Quotes can range from $400 to over $1,000. This is mostly labor cost, as the set of six high-quality plugs themselves usually costs between $70 and $150. Given the job's feasibility for DIY, many owners choose to do it themselves.
Does it matter which Denso or NGK plug I buy?
Yes, it's important to get the correct part number for your model year. The 2007-2015 models use a different plug than the 2016-2020 models. Always use a fitment guide to confirm the exact part number 🎬 See this specific walkthrough for 2016 and newer GS350 models. before purchasing. Using the wrong plug can lead to engine problems.
Helpful Videos
Technical Specifications
OEM Part Numbers: 90919-01249 (for 2007-2015 models) 90919-01263 (for 2016-2020 models)
Material: Iridium. Quantity Required: 6.
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The information in this article is provided for general reference and educational purposes only. Vehicle specifications, procedures, and part compatibility can vary by production date, trim level, and region. Always consult your vehicle's factory service manual and verify part numbers before purchasing or performing repairs. Safety-critical components such as airbags, seat belts, and braking systems should be installed by a qualified professional.
- Lexus GS350: