Best Spark Plugs For Ford Focus ST

When I bought my Focus ST, I knew the 2.0L EcoBoost engine was begging for tweaks. One of the easiest and most critical maintenance items that significantly impacts performance is the spark plug. Choosing the Best Spark Plugs For Ford Focus ST. isn’t just about finding cheap replacements; it’s about matching the right heat range and material to your driving style, especially if you’re running a tune. I’ve sifted through the market to put together this guide to help you keep your hot hatch running smoothly and powerfully.

IMAGE	PRODUCT NAME	AMAZON LINK
	4 pc NGK Iridium IX Spark Plugs compatible with Ford…	View on Amazon
	NGK Iridium IX Spark Plug LTR6IX-11 (4 Pack) for FORD…	View on Amazon
	4 pc NGK V-Power Spark Plugs compatible with Ford Focus…	View on Amazon
	UF670 Ignition Coil Pack 31316353 and Iridium Spark Plugs…	View on Amazon
	4 pc NGK Iridium IX Spark Plugs compatible with Ford…	View on Amazon
	A-Premium Iridium Platinum Spark Plugs Compatible with Ford…	View on Amazon
	Ignition Coil Pack Spark Plugs Combo fit for 2.0 2.3…	View on Amazon
	NGK 6510 LTR7IX-11 Iridium IX Spark Plug (4 Pack)	View on Amazon
	A-Premium Iridium Platinum Spark Plugs Compatible with Ford…	View on Amazon
	Ignition Coils & Spark Plugs for Ford Focus 2.0 2.3…	View on Amazon

4 pc NGK Iridium IX Spark Plugs compatible with Ford Focus 2.0L 2.3L L4 2012-2017

This 4-pack of NGK Iridium IX plugs is a fantastic option if you’re looking for a reliable, high-quality replacement for your standard Ford Focus or a mild stock tune on your ST (confirming the specific plug heat range is key here). Iridium is known for its incredible durability and ability to maintain a strong, consistent spark, which translates directly to improved throttle response and stable idle. These plugs come from a trusted OEM supplier, ensuring they meet the high demands of the EcoBoost engine.

Key features that stand out:
– Genuine NGK Parts: Ensures quality and reliability right out of the box.
– Iridium Construction: Provides excellent longevity and consistent spark delivery.
– Direct Replacement: Designed to fit specific 2.0L and 2.3L L4 Focus models.

Pros:
– Exceptional durability due to iridium center electrode.
– Reliable performance for daily driving and light spirited use.
– Comes with original packaging and hardware.

Cons:
– May not be the optimal heat range for aggressive aftermarket tunes on the ST.

Best for: Stock Focus ST or owners seeking a high-mileage replacement on standard Focus models.

Expert Opinion: This is a solid, dependable plug. While excellent for longevity, if you plan on pushing significant boost with a modified ECU tune, consider a step colder plug.

NGK Iridium IX Spark Plug LTR6IX-11 (4 Pack) for FORD FOCUS ST 2013-2014 2.0L/122

Specifically listed for the Ford Focus ST, the LTR6IX-11 utilizes a fine-wire iridium center electrode that ensures maximum durability under thermal stress. This design helps reduce required voltage, leading to fewer misfires and a smoother combustion cycle. For those running their ST close to stock or with minor bolt-ons and stock boost levels, this NGK plug is often considered the gold standard replacement for maintaining peak efficiency.

Key features that stand out:
– ST Specific Fitment: Confirmed compatibility for the 2.0L ST EcoBoost engine.
– Fine Wire Iridium: Promotes high durability and a consistently stable spark.
– High Melting Point Alloy: Ideal for high-performance, turbocharged applications.

Pros:
– Designed explicitly to handle the pressures of the ST engine.
– Excellent cold start and idling performance.
– Superior oxidation and corrosion resistance.

Cons:
– The specific heat range (6) might be too hot for highly tuned STs (Stage 3+).

Best for: Ford Focus ST owners looking for a premium stock-replacement plug that offers longevity and stability.

Expert Opinion: The LTR6IX-11 strikes a fantastic balance between performance and lifespan for daily driven STs. Always confirm the required gap, especially for turbocharged applications.

4 pc NGK V-Power Spark Plugs compatible with Ford Focus 2.0L 2.3L L4 2003-2010

While primarily aimed at older, naturally aspirated Focus models, the NGK V-Power plug is an excellent budget-friendly choice known for its reliable copper core performance. The V-groove center electrode directs the spark, improving ignitability and reducing fouling. If you happen to be replacing plugs on a non-ST Focus from the earlier generations and prioritize value over the extended lifespan of iridium, these are tough to beat.

Key features that stand out:
– V-Groove Center Electrode: Improves ignition and reduces quenching.
– Copper Core: Provides excellent conductivity and heat transfer.
– Economic Option: Reliable performance without the high cost of precious metals.

Pros:
– Extremely cost-effective maintenance solution.
– Consistent and reliable spark delivery.
– Excellent resistance to electrical wear.

Cons:
– Require more frequent replacement intervals compared to platinum or iridium plugs.

Best for: Owners of older (pre-2012) standard Ford Focus models seeking reliable, inexpensive replacements. (Not recommended for the 2013+ Focus ST EcoBoost).

Expert Opinion: Copper is the best conductor, but it burns out quicker. For the high heat and boost of the ST, stick with iridium or platinum, but for older cars, V-Power is a solid performer.

UF670 Ignition Coil Pack 31316353 and Iridium Spark Plugs Set Of 4 Fit For Ford Focus Fusion Explorer Edge Escape Mustang EcoSport Taurus 2012-2020&Land Rover 2012-2017&Lincoln 2013-2020 2.0L 2.3L L4

This all-in-one combo kit offers a major advantage: replacing both the ignition coils and the iridium spark plugs at once. Since the Focus ST runs high boost, the ignition system takes a beating. This kit ensures you have fresh coils and plugs, eliminating potential misfires caused by weak spark or worn components. The iridium plugs included are designed for long life, covering a wide range of Ford EcoBoost 2.0L and 2.3L engines, including the ST.

Key features that stand out:
– Complete Ignition Solution: Includes 4 coils (UF670) and 4 iridium plugs.
– Improved Reliability: Addresses common EcoBoost ignition issues simultaneously.
– Wide Fitment: Compatible with multiple 2.0L/2.3L Ford and Lincoln models.

Pros:
– Great value proposition for a full ignition refresh.
– Iridium plugs offer excellent longevity.
– One-year warranty provided.

Cons:
– Aftermarket coil quality can sometimes vary compared to genuine OEM parts.

Best for: Focus ST owners experiencing misfires or those performing a 100,000-mile comprehensive ignition system overhaul.

Expert Opinion: Replacing coils alongside plugs is smart preventative maintenance, especially on turbocharged engines where coils degrade faster. Ensure the included plugs are correctly gapped for your specific ST tune level.

4 pc NGK Iridium IX Spark Plugs compatible with Ford Focus 2.0L 2.3L L4 2012-2018

Similar to the previous NGK Iridium listing, this set provides coverage for slightly newer Focus models up to 2018. It maintains the same high standard of NGK quality, featuring the robust iridium alloy that resists corrosion and electrode wear, giving you peace of mind between service intervals. These are designed to be a direct fit, minimizing installation hassle for the DIY mechanic.

Key features that stand out:
– Extended Compatibility: Covers newer Focus models up to 2018.
– Excellent Durability: Known longevity that exceeds standard OEM requirements.
– Improved Ignition: Fine-wire tip provides consistent, powerful energy transfer.

Pros:
– Trusted brand reputation and genuine parts quality.
– Long replacement interval (typically 60k+ miles).
– Reliable performance across various driving conditions.

Cons:
– As a general fit part, you must manually confirm the heat range is suitable for your ST’s setup.

Best for: Focus owners who prioritize brand reliability and want a premium, long-lasting plug for routine maintenance.

Expert Opinion: When dealing with parts that cover a broad year range, always double-check the exact plug number against forum recommendations for your specific Focus ST year and modifications.

A-Premium Iridium Platinum Spark Plugs Compatible with Ford Focus 2012-2018, Transit Connect 2019-2021, EcoSport 2018-2020, 2.0L, Pack of 4

This A-Premium plug utilizes a dual precious metal construction: iridium tip and platinum core. This combination is engineered for maximum performance and outstanding longevity, with replacement intervals typically recommended between 80,000 and 100,000 miles. For the Focus ST driver who wants a high-quality plug without the NGK price tag, these offer robust ignitability and dependable service life.

Key features that stand out:
– Iridium Tip / Platinum Core: Dual precious metal design for maximum wear resistance.
– Extended Service Life: Engineered to last up to 100,000 miles.
– OEM Design: Engineered alongside OEMs for maximum ignition performance.

Pros:
– Exceptional mileage interval reduces maintenance frequency.
– Strong, focused spark thanks to the dual-metal design.
– Direct replacement fitment for 2.0L Focus models.

Cons:
– Slightly higher initial cost than standard copper plugs.

Best for: Focus owners focused purely on maximum mileage and reducing the frequency of plug replacement.

Expert Opinion: The iridium/platinum combination is fantastic for longevity. Be aware that running high boost on an ST may require tighter gapping than the factory 0.036-inch specification provided here.

Ignition Coil Pack Spark Plugs Combo fit for 2.0 2.3 Ford Escape Focus Transit Connect 2004 2005 2006 2007 2008 2009 2010 2011, 04 05 Mazda 3 6 Tribute Mercury Mariner, FD505 DG504, 4pcs

This package bundles four ignition coils and four pre-gapped spark plugs, offering a comprehensive repair solution, particularly for older Ford Focus generations (2005-2011). If you are driving an early model Focus that requires coil and plug replacement, this is a very efficient and affordable way to restore engine performance, smooth out a rough idle, and solve misfire issues.

Key features that stand out:
– Cost-Effective Combo: Includes 4 coils and 4 spark plugs.
– Addresses Performance Issues: Specifically designed to resolve misfires and rough idling.
– Pre-Gapped Plugs: Simplifies installation, though checking is still recommended.

Pros:
– Excellent solution for common ignition failures in older models.
– Affordable price point for a complete set.
– Meets or exceeds OEM specifications.

Cons:
– This specific kit is designed for earlier Focus models and is not suitable for the 2013+ Focus ST.

Best for: Focus owners (non-ST) from the 2004-2011 generation requiring a full ignition refresh.

Expert Opinion: Always check the exact OEM part numbers (like FD505/DG504) to confirm compatibility with your vehicle, as Ford used several different ignition coil designs over the years.

NGK 6510 LTR7IX-11 Iridium IX Spark Plug (4 Pack)

The NGK 6510, or LTR7IX-11, is famous in the Focus ST and EcoBoost community. The key difference here is the heat range: “7” is a step colder than the stock “6.” When you tune your ST (Stage 2 or higher), the engine runs hotter, requiring a colder plug to prevent pre-ignition (knock). This plug is often considered the benchmark requirement for modified STs, offering the proven reliability of Iridium IX with the necessary thermal characteristics for high boost.

Key features that stand out:
– Colder Heat Range (7): Essential for modified, higher-boost EcoBoost engines.
– Performance Focused: Ideal for tuned applications to prevent detonation.
– OEM Quality: NGK is the largest supplier of OEM spark plugs globally.

Pros:
– Dramatically reduces the chance of misfires and knock in tuned cars.
– Excellent longevity despite extreme operating conditions.
– Widely accepted as the best option for modified STs.

Cons:
– Might cause slightly rougher cold idle if used in a completely stock Focus ST.

Best for: Ford Focus ST owners running aftermarket tunes (Stage 2+) and requiring a colder plug to maintain engine safety.

Expert Opinion: If you have an accessport and are running a higher boost map, switching to the LTR7IX-11 is not optional—it’s mandatory for engine health. Remember to gap these tighter than stock (typically around 0.026–0.028 inches).

A-Premium Iridium Platinum Spark Plugs Compatible with Ford Explorer 2014-2019, Escape 2013-2019, Fusion, Focus 2013-2018, Mustang, Taurus, Special Service Police Sedan & Lincoln MKZ, MKC, Pack of 4

Another excellent iridium/platinum combination from A-Premium, this specific plug (Reference Number 96588, LTR6DI-8) targets the modern 2.0L and 2.3L EcoBoost engines, including the Focus ST 2013-2018. Like other dual-precious metal plugs, its main selling point is the combination of stability, robust spark delivery, and an exceptionally long replacement interval (80k–100k miles). The listed gap of 0.032 inches is also very close to the standard requirement for stock or lightly modified ST engines.

Key features that stand out:
– Broad EcoBoost Compatibility: Confirmed fitment for multiple high-performance Ford models, including the Focus ST.
– 0.032-inch Gap: Closer to required factory specification for the ST.
– CYFS-12Y-2 Reference: Matches a common Ford OEM part number for confidence.

Pros:
– Exceptional resistance to wear and tear.
– Long service life reduces maintenance frequency.
– Reliable spark delivery even under turbo pressure.

Cons:
– Must re-gap for heavily modified or race-focused ST setups.

Best for: Focus ST owners seeking OEM-equivalent performance and longevity using a trusted aftermarket brand.

Expert Opinion: This plug is a great choice if you prefer a plug designed closely to OEM standards, but remember that the advertised long lifespan should only be followed if you are running a stock configuration. Tuned cars should replace plugs far more frequently.

Ignition Coils & Spark Plugs for Ford Focus 2.0 2.3 2005-2007 Escape 2.3L 2005-2008 Transit Connect 2010-2013 for Mercury Mariner 2005-2008 for Mazda3 2004-2005 for Mazda6 2005 Tribut 2005-2008 DG507

This is another coil and plug combo kit, but specifically tailored toward the earlier 2.0L and 2.3L Focus models (2005-2007). It addresses aging ignition components in these vehicles, offering a comprehensive solution using the DG507 coil reference. If you maintain an older Focus, replacing both coils and plugs simultaneously is the best way to ensure the engine runs cleanly, eliminates stuttering, and improves overall efficiency.

Key features that stand out:
– Targeted Older Models: Ideal for 2005-2007 Focus and related Mazda/Mercury platforms.
– Includes 4 Coils and 4 Plugs: Complete ignition system refresh.
– OEM Cross-Reference: Coils match several OEM part numbers (DG507, FD505, etc.).

Pros:
– Restores lost performance in aging ignition systems.
– Convenient and cost-effective bundling.
– High-quality materials designed to meet or exceed original specs.

Cons:
– Not compatible with the 2013+ Focus ST EcoBoost model.

Best for: Owners of 2005-2007 standard Focus models requiring a full ignition system replacement.

Expert Opinion: While excellent for older models, ST owners need to focus on plugs designed specifically for the EcoBoost platform, which handle higher heat and pressure.

Comparison Insights: Stock vs. Tune and Iridium Choices

When sifting through these options to find the Best Spark Plugs For Ford Focus ST, we need to differentiate between simple replacements and performance upgrades.

The standard factory replacement plug for the Focus ST is typically an iridium or platinum plug with a heat range of “6” (like the LTR6IX-11). These are ideal if your car is 100% stock or only has a basic intake/exhaust setup. They offer a great balance of longevity and consistent spark.

If you are running an aggressive tune, especially Stage 2 or 3, you absolutely must upgrade to a colder plug. This is where the NGK 6510 LTR7IX-11 (Heat Range 7) shines. It pulls heat away from the tip faster, protecting your engine against damaging pre-ignition. If your ST is tuned, the LTR7IX-11 is your plug.

For general maintenance and budget concerns on non-ST models, combo kits (like the UF670 Ignition Coil Pack and Plugs) provide great value by refreshing the entire ignition system, which is crucial as the coils age. However, always verify the coil quality in aftermarket kits. If you are focused purely on minimizing replacement frequency, the dual Iridium Platinum plugs from A-Premium offer phenomenal mileage (80k–100k miles).

Final Verdict: Choosing the Right Plug for Your ST

Making the right choice depends entirely on your engine’s setup. Here is our recommended breakdown:

For the Stock or Lightly Modified Focus ST (Stock Tune/Stage 1):

We strongly recommend the NGK Iridium IX Spark Plug LTR6IX-11. It is specifically designed for the ST, offering proven reliability, excellent cold starts, and maximum durability at factory boost levels. It’s the most reliable “set it and forget it” option for daily drivers.

For the Tuned Focus ST (Stage 2, 3, or E30 Maps):

There is really only one primary choice: the NGK 6510 LTR7IX-11 Iridium IX Spark Plug. This step-colder plug is essential for safety, stability, and preventing high RPM misfires under increased boost pressure. Crucially, remember to gap this plug correctly (usually 0.026 to 0.028 inches) before installation.

For Comprehensive Ignition System Overhaul:

If your ST is older and you’re experiencing intermittent misfires, consider a high-quality kit that includes coils and plugs. While aftermarket coils can be a mixed bag, the convenience of the UF670 Ignition Coil Pack and Iridium Plugs makes it a compelling option, provided you check the coil performance after installation.

Frequently Asked Questions About the Best Spark Plugs for Ford Focus ST

Q1: Why do I need a different spark plug if I tune my Focus ST?

When you install an aggressive tune (like Stage 2 or 3), you increase the boost pressure and inject more fuel, which significantly raises the combustion chamber temperatures. The stock plug (heat range 6) may get too hot, causing the electrode tip to glow. This leads to pre-ignition or “knock,” which severely damages your EcoBoost engine. A colder plug, like the LTR7IX-11, transfers heat away faster, keeping the tip cool and preventing detonation.

Q2: What is the recommended spark plug gap for a stock Focus ST?

For a stock Ford Focus ST, the factory recommended gap is usually around 0.030 to 0.032 inches. However, if you are experiencing misfires, sometimes tightening this slightly to 0.028 inches can help. Always check the gap on any new plug, even if it is advertised as “pre-gapped,” especially when dealing with the high-pressure demands of the EcoBoost engine.

Q3: How often should I replace the spark plugs in my Focus ST?

If your ST is completely stock, most iridium plugs are rated for 60,000 to 100,000 miles. However, because the Focus ST is turbocharged and operates under high stress, most experienced owners recommend replacing them every 30,000 to 40,000 miles for reliable performance. If you are running a high-boost tune, you should inspect and potentially replace them every 10,000 to 15,000 miles.

Q4: Are copper or platinum spark plugs suitable for the Focus ST EcoBoost engine?

Generally, no. While copper has excellent conductivity, it doesn’t tolerate the intense heat and pressure of a modern direct-injection turbocharged engine like the ST’s EcoBoost. Platinum and especially Iridium offer far superior resistance to heat and wear, making them mandatory for the longevity and consistent performance of your Ford Focus ST ignition system.

Q5: What are the signs that my Focus ST spark plugs need replacing?

Common symptoms of failing spark plugs include engine misfires (especially under heavy acceleration), rough or unstable idle, difficulty starting the car, noticeable decrease in horsepower, and poor fuel economy. If you notice a hesitation or stutter when boosting, worn spark plugs are one of the first and easiest things to check.

Q6: Do I need to worry about the specific NGK part numbers (LTR6 vs. LTR7)?

Yes, these numbers are crucial. The number following the “LTR” (6 or 7) denotes the heat range. The “6” is a standard range suitable for stock engines, while the “7” is a colder plug critical for performance tunes. Using the wrong heat range can compromise performance or, worse, lead to engine damage if the plug is too hot for your modified setup.