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A Guide to Replacing Ignition Coils on Your 2011-2012 INFINITI G25

Diagnose and fix engine misfires by choosing the right ignition coils for your G25.

4 minutes to read 2011-2012 INFINITI G25
Difficulty
2/5
Est. Time
1.5 hrs
DIY Doable?
✅ Yes
Shop Labor
$150-$450
Used OEM Price
$20-$50
⚠️ Drivable, but... — Driving with a misfire for an extended period can cause unburned fuel to damage the catalytic converter, leading to a much more expensive repair.
Key Takeaways
  • A rough idle, shaking, and a check engine light with codes P0300-P0306 are the most common signs of a bad ignition coil.
  • Hitachi is the original equipment manufacturer; choosing this brand is the safest bet for quality and reliability.
  • While you can replace just the one failed coil, it's wise to replace all six (and the spark plugs) if they are high-mileage originals.
  • Do not drive for an extended period with a misfire, as you risk damaging your catalytic converters, a much more expensive repair.
Your INFINITI G25's V6 engine has six ignition coils. Each coil is a small but powerful transformer that sits directly on top of a spark plug. Its job is to take the 12-volt power from your car's battery and convert it into a very high voltage, sometimes over 20,000 volts. This high-voltage jolt creates a spark at the spark plug, which ignites the air and fuel mixture in the cylinder. This process, happening thousands of times per minute, is what powers your engine. When a coil fails, that cylinder stops working correctly, leading to noticeable engine problems.

Is Your G25 Running Rough? It Could Be an Ignition Coil

If your 2011-2012 INFINITI G25 suddenly develops a rough idle, starts shaking, or feels sluggish when you accelerate, a failing ignition coil is a very common cause. These coils are essential for smooth engine operation, but they are wear-and-tear items that eventually need replacement. This guide will help you understand the symptoms, choose the right aftermarket replacement, and know what to expect from the repair.

Can I Keep Driving with a Bad Ignition Coil?

You can, but it's not recommended for long. Driving with a misfire can cause unburned fuel to enter the exhaust, potentially damaging the expensive catalytic converter. It's best to address the issue as soon as possible to avoid a much costlier repair down the road.

How to Choose the Right Aftermarket Ignition Coil

When shopping for new aftermarket coils, you'll find a wide range of brands and prices. For a critical part like this, quality matters. Cheaper, unproven brands have a higher failure rate, which can leave you stranded and doing the job all over again. Here’s a breakdown of the brands available:

Tier 1: OEM & OEM-Equivalent Brands

These brands are either the original manufacturer for INFINITI or produce parts to the same high standards. They are the most reliable choice for a direct, trouble-free replacement.

  • Hitachi: Hitachi is the Original Equipment Manufacturer (OEM) for many Nissan and INFINITI ignition coils. Choosing Hitachi is like getting the genuine dealer part without the branded box and higher price tag. This is the most highly recommended option for G25 owners.
  • NGK: NGK is a world leader in ignition systems, famous for their spark plugs and coils. They are known for high-quality engineering and rigorous testing, making them an excellent and reliable alternative to Hitachi.
  • Delphi: Delphi is a major global parts manufacturer with a long history of supplying automakers. Their ignition coils are well-regarded and a solid choice for an OEM-quality replacement.

Tier 2: Reputable Aftermarket Brands

These brands offer a good balance of quality and price. They are a dependable choice for daily drivers.

  • Standard Ignition (Standard Motor Products): SMP is a long-standing aftermarket brand. Their standard red-box parts are generally considered good quality. Avoid their lower-cost "T-Series" line, which has a reputation for inconsistent quality.
  • Spectra: Spectra offers a range of aftermarket parts and can be a reliable mid-tier option.
  • Walker Products: Known for engine management and fuel system components, Walker provides dependable aftermarket solutions.

Tier 3: Value Brands

These brands focus on being the most affordable option. While the price is tempting, especially when buying a set of six, be aware that their long-term reliability may not match the higher-tier brands. These may include DriveWire, Global Parts, Skyward, True Tech, and others. For a sensitive engine like the G25's, it's generally wiser to invest in a better-known brand.

Pro Tip: Replace in Sets?

Ignition coils tend to fail around the same time. If one has failed and the others are original, it's a good preventative measure to replace all six at once. This is especially true since accessing the three coils on the driver's side requires more labor. While you're at it, it's the perfect time to replace your spark plugs if they are due.

🎬 See this walkthrough for replacing both your coils and spark plugs.

Cost of Replacing Ignition Coils on a 2011-2012 INFINITI G25

Part Type Cost per Coil Cost for Set of 6
New OEM (Dealer) $125 - $200 $750 - $1200
New Aftermarket (OEM-Quality) $70 - $150 $420 - $900
New Aftermarket (Value) $37 - $70 $222 - $420
Shop Labor $150 - $450 (Varies based on replacing one vs. all six)

Frequently Asked Questions

Do I need to replace all six coils at once?

You don't have to, but it's often recommended. Coils are exposed to the same heat and wear, so when one fails, others may soon follow. Since replacing the driver's side coils is more labor-intensive, replacing them all at once can save you time and money in the long run.

How do I know which coil is bad?

If your check engine light is on, a code scanner will point to a specific cylinder (e.g., P0301 for cylinder 1, P0302 for cylinder 2, etc.). A common diagnostic trick is to swap the suspected bad coil with a known good coil from another cylinder. Clear the codes, run the engine, and see if the misfire code "follows" the coil to the new cylinder. 🎬 Watch: A quick guide on how to diagnose a bad coil. If it does, you've confirmed the coil is faulty.

Are there any recalls for the G25 ignition coils?

No, there are no specific recalls for ignition coils on the 2011-2012 INFINITI G25.

Is replacing the ignition coils a DIY job?

Yes, it is feasible for a DIYer with some experience. The passenger side (Bank 1) coils are very easy to access. The driver's side (Bank 2) coils are more challenging as they are located under the intake air ducts and throttle bodies. You will need basic hand tools like a ratchet, sockets, and extensions.

🎬 Watch: This step-by-step video shows the full replacement process.
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Technical Specifications

OEM Part Numbers: 22448-JA10C 22448-JA11C

Engine: VQ25HR 2.5L V6, Quantity Required: 6, Type: Coil-on-Plug (COP), Connector Terminals: 3

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Article researched & written by
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Meet Wrenchy → Updated Apr 19, 2026

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.

Year Coverage
This article covers the Ignition Coil for:
  • INFINITI G25: 20112012
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