A Guide to Ignition Coils for the 2003-2012 INFINITI FX35
Solve engine misfires and restore performance in your FX35 by understanding how to choose the right replacement ignition coils.
- For reliability, choose Hitachi (the OEM supplier), NGK, or Delphi coils.
- On 2003-2008 models, investigate the grounding issue outlined in TSB ITB11-017a to prevent repeat failures.
- Always check for oil in the spark plug tubes, as a leaking valve cover gasket is a common cause of coil failure.
- It is highly recommended to replace all six coils and spark plugs at the same time for best results.
Is Your FX35 Running Rough? It Could Be an Ignition Coil.
A failing ignition coil is a common issue that can cause noticeable engine problems. Because your FX35 has six coils, the failure of just one can disrupt the engine's balance, leading to poor performance and potential damage if ignored. Understanding the symptoms and how to choose a quality replacement part is key to keeping your VQ engine running strong.
Symptoms of a Bad Ignition Coil
When a coil starts to fail, your FX35 will give you clear warning signs. The most obvious is a Check Engine Light. If the light is flashing, it signals a serious misfire that could damage your expensive catalytic converters, so you should reduce speed and have it checked immediately.
- Rough Engine Performance: You may feel sputtering, hesitation when you accelerate, or a general loss of power.
- Vibrations at Idle: The engine may shake or vibrate more than usual when you're stopped at a light.
- Reduced Fuel Economy: A misfiring cylinder forces the engine to work harder and burn more gas.
- Difficulty Starting: The engine may crank longer than usual before starting, or it might stall right after it starts.
- Gasoline Smell: A weak or absent spark can leave unburnt fuel that escapes through the exhaust.
Known Issue for 2003-2008 Models: Grounding Problems
For first-generation (S50) FX35s, INFINITI issued Technical Service Bulletin (TSB) ITB11-017a. This TSB addresses cases where ignition coils fail and appear blistered or melted. The problem is often caused by a poor ground connection, not the coil itself. The official fix involves cleaning specific engine ground points and replacing the negative battery cables. If you have a 2003-2008 model with a failed coil, it is critical to check these grounds to prevent repeat failures.
Choosing the Right Aftermarket Ignition Coil
When shopping for new ignition coils, you'll find many brands at different prices. For the FX35's VQ-series engine, quality matters. Sticking to proven brands can save you from doing the job twice.
Tier 1: OEM Supplier & Premium Aftermarket
These brands are known to meet or exceed original equipment standards and are highly recommended by FX35 owners.
- Hitachi: Hitachi is the Original Equipment Manufacturer (OEM) for Nissan/INFINITI. Choosing a Hitachi coil is the closest you can get to the factory part without the dealership price tag. They are a top choice for reliability and performance.
- NGK: Famous for their spark plugs, NGK also produces high-quality ignition coils that are well-regarded for their durability and performance.
- Delphi: Delphi is another major OEM supplier for many car brands and has a strong reputation for producing reliable ignition components.
Tier 2: Standard Aftermarket
These brands offer a balance of value and quality. They are a good option for budget-conscious repairs.
- Standard Motor Products (SMP)
- Walker Products
- Hella
Tier 3: Economy Brands
These brands offer the lowest price but may have a shorter service life and less consistent performance. They can be a viable option for an immediate, temporary fix.
- DriveWire
- Global Parts
- True Tech / Skyward
Pro Tip: Check for Oil Leaks!
A very common cause of ignition coil failure on the FX35 is a leaking valve cover gasket. Oil seeps into the spark plug tubes and soaks the bottom of the coil, causing it to short out and fail. When you remove the old coil, look for oil in the tube or on the coil boot. If you see oil, you must replace the valve cover gaskets to solve the root problem.
🎬 See how to replace leaking valve cover gaskets on your FX35.Cost to Replace INFINITI FX35 Ignition Coils
The cost can vary significantly based on the brand of parts you choose and whether you do the work yourself.
| Item | Estimated Cost |
|---|---|
| New OEM Ignition Coil (Set of 6) | $600 - $800+ |
| New Aftermarket Ignition Coil (Set of 6) | $120 - $300 |
| Shop Labor | $150 - $375 |
| DIY Total (Premium Aftermarket Coils) | $170 - $250 |
| Shop Total (Premium Aftermarket Coils) | $320 - $625 |
Frequently Asked Questions
Should I replace all six ignition coils at once?
Yes. Ignition coils are wear items that tend to fail around the same time. If one has failed due to age and mileage, the others are likely not far behind. Replacing all six at once is a best practice that saves you from repeated repairs.
Should I replace my spark plugs with the ignition coils?
Absolutely. You have to remove the ignition coils to get to the spark plugs anyway, so you will save on future labor costs. Worn spark plugs can also strain the ignition coils, so installing new plugs and coils together ensures the entire ignition system is healthy.
Is it hard to replace the ignition coils myself?
No, this is a great DIY job for beginners. 🎬 Watch this step-by-step guide to replacing your coils and plugs. The coils are easily accessible on top of the engine. Each one is held by a single 10mm bolt. The only tool you need is a basic socket set. The driver's side requires removing the air intake tube, which is also straightforward.
What are the OBD-II codes for a bad ignition coil?
A general misfire is code P0300. Cylinder-specific misfire codes are P0301 through P0306, which tell you exactly which cylinder is having a problem. For example, P0304 points to a misfire on cylinder 4. You may also see codes from P0350 to P0362, which point more directly to a fault in the coil's electrical circuit.
🎬 Learn how to diagnose specific misfire codes with this video.Helpful Videos
Technical Specifications
OEM Part Numbers: 22448-AL61C 22448-AL615 22448-JA10C 22448-JA11C
System Type: Coil-on-Plug (COP), Quantity per Vehicle: 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.
- INFINITI FX35:
- 🎬 Helpful Videos
- 🛍️ Shop This Part
- Is Your FX35 Running Rough? It Could Be an Ignition Coil.
- Symptoms of a Bad Ignition Coil
- Known Issue for 2003-2008 Models: Grounding Problems
- Choosing the Right Aftermarket Ignition Coil
- Tier 1: OEM Supplier & Premium Aftermarket
- Tier 2: Standard Aftermarket
- Tier 3: Economy Brands
- Pro Tip: Check for Oil Leaks!
- Cost to Replace INFINITI FX35 Ignition Coils
- Frequently Asked Questions
- 🎟️ Get 5% Off