A Guide to Replacing Ignition Coils on Your 2008-2012 INFINITI EX35
Fix engine misfires and restore lost power by choosing the right ignition coils for your V6 engine.
- Hitachi is the original equipment (OEM) supplier; buying this brand offers OEM quality without the dealer price.
- It is highly recommended to replace all six coils at once to ensure reliability and save on future labor.
- A persistent misfire can damage your catalytic converter, a much more expensive repair. Address a flashing check engine light immediately.
- If you experience repeated coil failures, investigate the grounding issue described in TSB ITB11-017a.
Is Your EX35 Running Rough? It Could Be an Ignition Coil.
Ignition coil failure is a common issue on many vehicles as they age, including the 2008-2012 INFINITI EX35. When a coil starts to fail, it can't produce a strong enough spark, leading to a variety of noticeable engine problems. Because the symptoms can be alarming, it's important to diagnose the issue correctly to avoid unnecessary repairs.
Symptoms of a Failing Ignition Coil
A bad ignition coil on your EX35 will make itself known. Here are the most common signs:
- Engine Misfires: This is the most obvious symptom. You'll feel a shudder, hesitation, or jerking from the engine, especially when accelerating or stopped at a light.
- Rough Idle: When your car is stopped in "Drive," the engine may shake or vibrate more than usual.
- Check Engine Light: A failing coil will almost always trigger the check engine light. The light may be solid or flashing. 🎬 Watch: How to diagnose a misfire when your light flashes. A flashing light indicates a severe misfire that could damage other components.
- Loss of Power: Your EX35 may feel sluggish and slow to accelerate.
- Poor Fuel Economy: When a cylinder isn't firing correctly, fuel is wasted, and you'll notice you're filling up more often.
- Engine Codes: The most common trouble codes are P0300 (Random Misfire) and P0301 through P0306 (indicating a misfire in a specific cylinder, 1 through 6). You may also see codes from P0351 to P0356, which point directly to a fault in the ignition coil circuit.
Known Issues: A Grounding Problem (TSB ITB11-017a)
While there are no official recalls for ignition coils on the EX35, INFINITI has issued a Technical Service Bulletin (TSB) for similar models that addresses repeated coil failures. The TSB, ITB11-017a, notes that in some cases, blistering or melting coils and persistent misfire codes are caused by a poor grounding connection. The fix involves cleaning engine ground points and replacing specific negative battery cables and bolts. If you have replaced coils before and they failed again, this grounding issue is the likely culprit.
Choosing the Right Aftermarket Ignition Coil
Not all aftermarket coils are created equal. For a vehicle like the INFINITI EX35, choosing a quality part is key to restoring performance and reliability. The brands available can be grouped into tiers.
Pro Tip: Many owners and mechanics strongly recommend replacing all six ignition coils at the same time. When one fails due to age and heat, the others are often not far behind. This saves you from repeated repairs and ensures balanced engine performance.
Tier 1: OEM Supplier (Best Quality)
Hitachi is widely confirmed by INFINITI owners and mechanics to be the Original Equipment Manufacturer (OEM) for the ignition coils used in the VQ35HR engine. This means buying a Hitachi-branded coil is the same as getting the part from the dealer, but without the dealership price. For reliability and peace of mind, Hitachi is the top choice.
- Brands: Hitachi, NGK
- Assessment: Excellent quality and perfect fit. NGK is another top-tier Japanese brand known for ignition components and is also a trusted option.
Tier 2: Reputable Aftermarket
These brands are known for producing quality parts that meet or exceed OEM specifications. They are a solid choice if OEM-supplier parts are not available or if you're looking for a balance of quality and price.
- Brands: Delphi, Standard Ignition, Walker Products
- Assessment: Good, reliable quality. These companies have a long history in the aftermarket and generally offer a good warranty and dependable performance.
Tier 3: Value Brands
These are the most budget-friendly options. While the low price is attractive, quality and longevity can be inconsistent. These are best used for a temporary fix or if you plan on selling the vehicle soon.
- Brands: DriveWire, Skyward, True Tech, Global Parts
- Assessment: Use with caution. Forum discussions often contain stories of these cheaper coils failing prematurely. If long-term reliability is your goal, it's often worth spending more on a Tier 1 or Tier 2 brand.
| Part Type | Price Range | Notes |
|---|---|---|
| New OEM (Dealer) | $60 - $90 | Highest price, identical to Hitachi. |
| New Aftermarket (OEM Supplier) | $35 - $55 | Best value. Hitachi is the recommended brand. |
| New Aftermarket (Value) | $20 - $40 | Lower price, but potentially lower quality and shorter lifespan. |
| Shop Labor to Replace | $100 - $225 | Covers 1-1.5 hours of work. Price varies by shop. |
Frequently Asked Questions (FAQ)
Can I drive my EX35 with a bad ignition coil?
You can, but it is not recommended for an extended period. Driving with a constant misfire allows unburned fuel to enter the exhaust system, which can quickly damage the expensive catalytic converters, leading to a much costlier repair.
Is replacing the ignition coils a DIY job?
Yes, for many people it is. The coils are located on top of the engine. The three coils on the passenger side are very easy to access. The three on the driver's side are under the air intake duct, which must be removed. The job requires basic hand tools 🎬 See this walkthrough for replacing VQ35HR spark plugs and coils. and should take 1-2 hours.
How do I know which coil is bad?
If you have an OBD-II scanner, the code will tell you (e.g., P0304 means cylinder 4 is misfiring). A simple diagnostic trick is to swap the suspected bad coil with a known good coil from another cylinder. Clear the codes, run the engine, and scan again. If the misfire code "follows" the coil to the new cylinder (e.g., the code changes to P0302 after moving the coil from cylinder 4 to 2), you've confirmed the coil is bad.
Should I replace the spark plugs at the same time?
It's a great idea. The ignition coils have to be removed to access the spark plugs anyway, so you will save on future labor costs. 🎬 Watch: Step-by-step spark plug replacement guide for your EX35. Worn spark plugs can also strain the ignition coils, so replacing them together ensures the entire ignition system is healthy.
Helpful Videos
Technical Specifications
OEM Part Numbers: 22448-JA10C 22448-JA11C 22448-EY00A
This vehicle uses a 6-cylinder VQ35HR engine, which requires six individual coil-on-plug ignition coils. The OEM supplier is Hitachi, part number IGC0007.
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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 EX35:
- 🎬 Helpful Videos
- 🛍️ Shop This Part
- Is Your EX35 Running Rough? It Could Be an Ignition Coil.
- Symptoms of a Failing Ignition Coil
- Known Issues: A Grounding Problem (TSB ITB11-017a)
- Choosing the Right Aftermarket Ignition Coil
- Tier 1: OEM Supplier (Best Quality)
- Tier 2: Reputable Aftermarket
- Tier 3: Value Brands
- Frequently Asked Questions (FAQ)
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