A Guide to Spark Plug Replacement for the 2014-2017 Infiniti QX70
Keep your QX70's V6 engine running strong by understanding its spark plug needs.
- Only use Iridium spark plugs from reputable brands like Denso, NGK, or Bosch; the QX70's engine is designed for them.
- The standard replacement interval is around 100,000 miles, but symptoms like a rough idle or poor MPG may signal an earlier need.
- DIY replacement is possible but requires removing the dual throttle bodies to access all six plugs.
- A flashing check engine light is a serious symptom; pull over immediately to prevent expensive catalytic converter damage.
Signs of Failing Spark Plugs
Worn spark plugs can cause several noticeable problems in your QX70. As the electrodes on the plugs wear down, the gap the spark must jump becomes wider, requiring more energy and leading to a weaker spark. This can result in a variety of symptoms that affect your driving experience.
- Rough Idle: Your engine may feel shaky or uneven when the car is stopped.
- Reduced Fuel Economy: Inefficient combustion means you'll be visiting the gas station more often.
- Engine Misfires: You might feel a hesitation or stumble during acceleration. This can trigger a check engine light with codes like P0300 (random misfire) or P0301-P0306 (for specific cylinders). 🎬 See how to diagnose a misfire on these Infiniti engines.
- Difficulty Starting: A weak spark can make it harder for the engine to turn over, especially in cold weather.
- Poor Acceleration: Your QX70 may feel sluggish or less responsive than usual.
A Note on the Check Engine Light
If your check engine light is flashing, it indicates a severe misfire. You should pull over and stop driving as soon as it is safe. Continuing to drive with a flashing check engine light can cause unburned fuel to enter the exhaust, potentially leading to catastrophic damage to the catalytic converters, a very expensive repair.
Choosing the Right Aftermarket Spark Plugs
Your 2014-2017 QX70 came from the factory with high-quality, long-life iridium spark plugs. It is highly recommended to use iridium plugs for replacement. Cheaper copper or standard platinum plugs are not designed for this engine's high-energy ignition system and will cause poor performance and require much more frequent replacement.
| Brand Tier | Brands | Quality & Performance Assessment |
|---|---|---|
| OEM & Premium Tier | Denso, NGK | Denso and NGK are the original equipment suppliers for Infiniti. Choosing their iridium options (like Denso Iridium Long-Life or NGK Laser Iridium) guarantees a perfect fit and factory-level performance and longevity, often exceeding 100,000 miles. These are the best choice for your vehicle. |
| Quality Alternative Tier | Bosch | Bosch Double Iridium plugs are a strong alternative. They are known for durability and consistent performance, providing a reliable spark and a long service life that makes them a great value. |
| Standard Tier | Champion | Champion offers iridium plugs that are a budget-friendly option. While they provide reliable performance for daily driving, their longevity may not match that of the premium brands. |
Pro Tip: Stick with Iridium
The VQ37VHR engine in your QX70 is designed specifically for iridium spark plugs. Using anything less will compromise performance and require you to do this job again much sooner. The small extra cost for iridium plugs is well worth it for the performance and 100,000-mile service interval.
Known Issues, Recalls, and TSBs
As of early 2026, there are no specific recalls or widespread Technical Service Bulletins (TSBs) from Infiniti directly concerning spark plug failure on the 2014-2017 QX70. However, misfire codes (P0300-P0306) are often the first sign of worn plugs. In some cases, oil leaking into the spark plug tubes from a failing valve cover gasket can cause misfires and damage both the spark plugs and ignition coils. If you find oil on the porcelain part of your old plugs during replacement, the valve cover gaskets should also be replaced.
🎬 Watch: How to replace leaking valve cover gaskets on your QX70.Frequently Asked Questions (FAQ)
When should I replace the spark plugs on my QX70?
The recommended replacement interval for the original iridium spark plugs is approximately every 100,000 to 105,000 miles. However, driving habits and conditions can affect their lifespan. It's wise to inspect them if you experience any failure symptoms, even before this mileage.
Do I need to replace the ignition coils at the same time?
It is not required, but it is often recommended as preventative maintenance, especially on high-mileage vehicles. The ignition coils must be removed to access the spark plugs, so replacing them at the same time saves on redundant labor costs. If you are not experiencing misfires, you can likely reuse the original coils.
What is a spark plug gap, and do I need to check it?
The gap is the tiny space between the center and ground electrodes. High-quality iridium spark plugs for your QX70 come pre-gapped from the factory and should not be adjusted. The fine iridium tip is fragile and can be easily damaged by a gapping tool. Always check that the box and plug haven't been damaged in shipping, but do not attempt to gap them.
Is replacing the spark plugs a DIY job?
For an experienced DIYer, yes. However, it is more complex than on many other vehicles. To access all six spark plugs on the VQ37VHR engine, the dual throttle bodies and intake air ducts must be removed. This can be intimidating for a novice. If you are not comfortable with this, it's best to leave it to a professional mechanic.
🎬 Watch: A complete 3.7L tune-up and spark plug replacement walkthrough.Helpful Videos
Technical Specifications
OEM Part Numbers: 22401-JK01D
The 2014-2017 Infiniti QX70 with the 3.7L V6 engine requires a set of six iridium-tipped spark plugs. The factory-installed plugs are typically Denso model FXE24HR11. The recommended gap is pre-set and should not be adjusted.
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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.
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