A Comprehensive Guide to Spark Plugs for the 2008-2009 Ford Taurus X
If your Ford Taurus X is running rough or losing power, it might be time for new spark plugs.
- To replace the three rear spark plugs, the upper intake manifold must be removed, making the job moderately difficult.
- If you have misfire codes P0351-P0356, check TSB 13-4-17, as you may need to replace the PCM, coils, and plugs.
- Use high-quality iridium or platinum plugs from brands like Motorcraft, NGK, or Denso for the best longevity and performance.
- Always verify the spark plug gap is between 0.049-0.053 inches before installation.
Symptoms of Failing Spark Plugs
Worn or fouled spark plugs can cause noticeable problems in your Taurus X. Because the engine relies on a clean spark for efficient combustion, you might experience a variety of symptoms when the plugs are failing. These signs are your engine's way of telling you it needs attention.
- Rough Idling: The engine may shake or vibrate more than usual when the vehicle is stopped.
- Reduced Fuel Economy: You may find yourself filling up the gas tank more often as the engine works less efficiently.
- Poor Acceleration: The vehicle may feel sluggish or hesitant when you press the gas pedal.
- Engine Misfires: You might feel a stutter or stumble from the engine during acceleration. A flashing Check Engine Light is a sure sign of a misfire.
- Difficulty Starting: The engine may take longer to crank before it starts, or it may not start at all.
Known Issue: Check for TSB 13-4-17
For 2008 Taurus X models built on or before March 1, 2008, there is a Technical Service Bulletin (TSB 13-4-17) you should be aware of. This TSB addresses an issue where a faulty Powertrain Control Module (PCM) can damage the ignition coils, leading to misfire codes like P0351 through P0356. If you have these specific codes, the problem may not be just the spark plugs. The official procedure requires inspecting the ignition coils for damage and, if found, replacing the PCM, all six ignition coils, and all six spark plugs at the same time.
🎬 Watch a professional guide on replacing your ignition coils.Choosing the Right Aftermarket Spark Plugs
The original spark plugs in your Taurus X were made by Motorcraft. While you can certainly use Motorcraft plugs as replacements, high-quality aftermarket brands often provide equal or even better performance and longevity. The key is to choose the right material and a reputable brand.
Brand Tiers for Your Taurus X
- Top Tier (Iridium): Brands like NGK and Denso are highly recommended by mechanics and enthusiasts. Their iridium spark plugs offer the best performance and longest service life, often lasting up to 100,000 miles. They provide a strong, consistent spark that helps maintain fuel economy and engine power over time. The NGK Laser Iridium and Denso Iridium TT are excellent choices.
- Mid-Grade (Platinum): Autolite and Bosch offer double platinum plugs that are a good step up from basic copper plugs and are more affordable than iridium. Autolite has a long history with Ford and is often considered a direct equivalent to Motorcraft. These are a solid, reliable choice for daily driving.
- Standard Grade: Basic copper plugs from brands like Champion are available, but they have a much shorter service life and are not recommended for the coil-on-plug ignition system in the Taurus X. For the small price difference, investing in at least a platinum plug is worthwhile.
Installation Is Key
The spark plug replacement on the 3.5L V6 is a tale of two halves. The front three plugs (closest to the radiator) are easy to access. However, the rear three plugs are located under the upper intake manifold, which must be removed to gain access. This makes the job more complex and time-consuming. While it is possible for a DIYer with some experience, many owners choose to have a professional handle it. If you do it yourself, make sure to also get new intake manifold gaskets.
🎬 See how to remove the upper intake manifold on this engine.Cost of Replacing Spark Plugs
The cost can vary depending on whether you do the work yourself or hire a shop. The parts themselves are not expensive, but the labor for the rear plugs adds to the cost.
| Item | Estimated Cost |
|---|---|
| Aftermarket Spark Plugs (Set of 6) | $35 - $125 |
| Shop Labor | $250 - $350 |
| Total Professional Installation | $375 - $441 |
Frequently Asked Questions
Do I have to replace all six spark plugs at once?
Yes. Spark plugs wear out at a similar rate. Replacing all of them at the same time ensures balanced engine performance and prevents you from having to repeat the labor-intensive job of removing the intake manifold a few months later when another old plug fails.
Is the spark plug replacement difficult on the 2008-2009 Taurus X?
It is considered moderately difficult. While the front three plugs are straightforward, accessing the rear three requires removing the upper intake manifold. This adds significant time and complexity to the job compared to an engine where all plugs are easily accessible.
What spark plug gap is required for the Taurus X?
The correct spark plug gap is between 0.049 and 0.053 inches (1.25mm - 1.35mm). While most iridium and platinum plugs come pre-gapped, it is crucial to check and adjust the gap if necessary before installation. An incorrect gap can cause misfires and poor performance.
Do I need to worry about the spark plugs breaking during removal?
The 3.5L Duratec engine in your Taurus X does NOT use the problematic two-piece spark plugs found in some other Ford engines of the era (like the 5.4L V8). However, it is still wise to let the engine cool down completely and work carefully to avoid damaging the threads in the aluminum cylinder heads. Some mechanics recommend slightly warming the engine for a few minutes to help ease removal.
Helpful Videos
Technical Specifications
OEM Part Numbers: SP-411 AYFS-22F-M
Spark Plug Gap: 0.049 - 0.053 in (1.25mm - 1.35mm)
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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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