Best Spark Plugs For Ford Flex

When I first bought my Ford Flex, I knew the 3.5L V6 engine was built for the long haul, but eventually, even the best engines need fresh ignition components. Digging through all the options for Ford Flex spark plug replacement can be overwhelming, especially when trying to choose between Iridium and Platinum options. I’ve spent time testing and comparing the top contenders to help you get the smoothest performance and best gas mileage. This guide breaks down the 10 best spark plugs for Ford Flex, so you can choose the right component for your SUV’s specific needs, whether you have the naturally aspirated or EcoBoost model.

IMAGE	PRODUCT NAME	AMAZON LINK
	6 pc Champion Platinum Spark Plugs compatible with Ford…	View on Amazon
	Set of 6 Ignition Coil Pack and Spark Plugs Fits…	View on Amazon
	A-Premium Iridium Platinum Spark Plugs Compatible with Ford…	View on Amazon
	Iridium Spark Plugs 6 Pack 94374 LTR6IX Fit for 2011-2020…	View on Amazon
	Iridium Spark Plugs 6 Pack 97177 Fits for 2011-2019 Ford…	View on Amazon
	MAS Set of 6 Ignition Coil Pack & 6Pcs Motorcraft…	View on Amazon
	MAS 6Pcs Ignition Coil Pack & 6Pcs Motorcraft Platinum…	View on Amazon
	MCK 6pcs Ignition Coil Pack And Motorcraft Iridium Spark…	View on Amazon
	A-Premium Iridium Platinum Spark Plugs Compatible with Ford…	View on Amazon
	ECCPP UF553 6 ignition coils with 6 iridium Spark Plugs…	View on Amazon

6 pc Champion Platinum Spark Plugs compatible with Ford Flex 3.5L V6 2009-2019

If you’re looking for a name trusted in performance, Champion delivers. This set of 6 Platinum spark plugs is designed as a direct replacement for the Ford Flex 3.5L V6 models spanning a full decade. The use of durable platinum ensures a long service life and reliable starts, making this an excellent choice for routine maintenance. Champion emphasizes their racing heritage, translating that experience into a durable and powerful spark for your daily driver.

Key features that stand out:
* Decade-Spanning Compatibility: Fits 3.5L V6 Ford Flex models from 2009 through 2019.
* Genuine Quality: Direct replacement auto parts that meet high industry standards.
* Platinum Construction: Built with durable precious metals for improved performance and minimized wear.

Pros:
* – Excellent long-lasting quality due to precious metal construction.
* – Reliable brand recognized for ignition expertise.
* – Proven performance improvement for standard maintenance.

Cons:
* – May not offer the extreme longevity of some Iridium options.

Best for: Ford Flex owners seeking a trusted, high-quality Platinum plug replacement for standard engine maintenance.

Expert Opinion: Champion is a staple in the automotive world. These platinum plugs provide consistent, reliable performance without the higher cost associated with full Iridium plugs, making them a great maintenance choice.

Set of 6 Ignition Coil Pack and Spark Plugs Fits for 3.7 3.5 V6 Ford Edge Flex Taurus Lincoln MKS MKT MKZ MKX Mercury Sable 2008 2009 2010 2011 2012 2013 2014 2015 2016 UF553 5019

Sometimes, when your spark plugs start failing, your ignition coils aren’t far behind. This comprehensive kit solves the problem by providing both the coil packs and the spark plugs in one convenient package. This bundle is perfect for a full tune-up, aiming to restore lost power, eliminate misfires, and improve overall fuel economy by upgrading 15% more energy than standard OE coils.

Key features that stand out:
* Full Tune-Up Bundle: Includes 6 ignition coils (UF553) and 6 spark plugs.
* Enhanced Performance: Coils are designed with highly conductive copper wire for superior connectivity.
* Direct OEM Design: Simple installation and guaranteed fitment for the specified 3.5L V6 engines.

Pros:
* – Excellent value since both coils and plugs are included.
* – Designed to eliminate common issues like misfires and poor gas mileage.
* – High-quality copper wiring for enhanced durability.

Cons:
* – The brand is less established than true OEM providers, requiring careful verification of quality control.

Best for: Flex owners needing a complete ignition system overhaul to solve persistent misfiring or hesitation issues.

Expert Opinion: Bundled kits like this are ideal for the Flex, as replacing plugs often requires accessing challenging spots, and doing the coils at the same time is very practical. This is a cost-effective way to get back superior cold-start performance.

A-Premium Iridium Platinum Spark Plugs Compatible with Ford Fusion 2010-2012, Edge 2007-2011, Taurus 2008-2012, Taurus X 2008-2009, Flex 2009-2012 & Lincoln MKZ, MKX, MKS, MKT, Pack of 6

A-Premium brings a fantastic blend of materials with this Iridium Platinum spark plug set. By combining an Iridium tip with a Platinum core, these plugs are engineered for maximum ignition performance and exceptional longevity. They are specifically recommended for replacement intervals between 80,000 to 100,000 miles, which is great news for high-mileage drivers.

Key features that stand out:
* Dual Precious Metal Design: Iridium center tip and Platinum core for superior heat resistance and wear.
* High Longevity: Engineered to last significantly longer than standard copper or single-platinum plugs.
* Specific Gap Size: Comes pre-gapped at 0.052″ (always verify with your manual).

Pros:
* – Extended replacement interval saves time and labor costs.
* – Exceptional ignitability ensures smooth starts.
* – Robust material construction resists electrical wear.

Cons:
* – Compatibility is restricted to the earlier Ford Flex models (up to 2012 naturally aspirated).

Best for: Flex owners with earlier models (2009-2012) prioritizing extremely long service life and reliability.

Expert Opinion: The combination of Iridium and Platinum is highly effective for modern engines. This plug is a great option if you hate doing spark plug changes frequently, offering set-it-and-forget-it performance for nearly 100k miles.

Iridium Spark Plugs 6 Pack 94374 LTR6IX Fit for 2011-2020 Ford F150 3.5 V6 Expedition Explorer Flex Taurus Transit-150 250 & Lincoln MKS MKT Navigator 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020

This all-Iridium spark plug set offers broad compatibility across many Ford 3.5L V6 applications, including the 2011-2020 Ford Flex. The rigorous quality control aims to combat all common ignition system issues like backfiring, poor idling, and vehicle shaking. Iridium is known for its extreme melting point, making these plugs perfect for sustained high-performance driving.

Key features that stand out:
* Wide Application: Fits Flex models across nearly a decade (2011-2020 3.5L V6).
* Strict Quality Control: Designed to stabilize high voltage output across all engine speed ranges.
* Performance Focused: Specifically built to improve power delivery and engine smoothness.

Pros:
* – Excellent choice for newer Flex models and related EcoBoost variants (verify gap).
* – Improves stability and reliability under various driving conditions.
* – Comprehensive warranty offers peace of mind.

Cons:
* – Users must confirm the correct gap size, especially for turbocharged applications.

Best for: Ford Flex owners seeking pure Iridium performance and long-term durability across various model years.

Expert Opinion: The LTR6IX standard is highly respected in the industry. These plugs are particularly good at maintaining a consistent spark even when the engine is under heavy load, translating directly into better acceleration and responsiveness.

Iridium Spark Plugs 6 Pack 97177 Fits for 2011-2019 Ford F150 3.5 Explorer Taurus Flex Expedition Transit 150 250 350 Lincoln MKS MKT Navigator 2011 2012 2013 2014 2015 2016 2017 2018 2019 V6 3.5L

Focusing heavily on efficiency, the 97177 Iridium spark plugs feature an ultra-fine wire center electrode design (0.6mm). This innovative construction, combined with laser-welded technology, means you get a more concentrated and powerful spark, leading directly to maximum fuel efficiency and minimized consumption. The Iridium alloy is six times harder than platinum, guaranteeing exceptional longevity.

Key features that stand out:
* Exceptional Fuel Efficiency: 0.6mm fine-wire Iridium center tip improves combustion.
* Extreme Durability: Iridium alloy offers an extremely high melting point and resistance to electrical wear.
* OE Reference Compatibility: Matches several common Ford OE part numbers (BL3E-12405-CA, etc.).

Pros:
* – Excellent choice for Flex owners prioritizing gas mileage improvement.
* – Superior material hardness ensures a very long service life.
* – Consistent performance in high-heat, high-performance engines.

Cons:
* – The initial cost is higher than standard copper or simple platinum plugs.

Best for: Ford Flex drivers looking to maximize their miles-per-gallon (MPG) through precision ignition technology.

Expert Opinion: When talking about pure longevity and efficiency, Iridium fine-wire designs are the gold standard. This plug delivers a reliable, robust spark that benefits both EcoBoost and naturally aspirated Flex engines.

MAS Set of 6 Ignition Coil Pack & 6Pcs Motorcraft Platinum Spark Plug SP589 Compatible with Lincoln MKS MKT MKX MKZ Ford Edge Flex Fusion Taurus 3.7 3.5 V6 Replacement for UF553 5C1652 DG520

If you trust the factory brand, this MAS bundle is attractive because it pairs MAS ignition coils with Genuine Motorcraft Platinum Spark Plugs (SP589). Motorcraft is the OEM component supplier for Ford, meaning these spark plugs offer the closest performance and fitment to what came in your Flex from the factory. Crucially, the seller clearly notes these components are NOT suitable for turbocharged (EcoBoost) engines, making them a straightforward choice for the standard 3.5L V6.

Key features that stand out:
* OEM Spark Plugs: Includes Motorcraft SP589 Platinum plugs.
* Complete Ignition Overhaul: Six coils and six plugs included in the package.
* Naturally Aspirated Focus: Clearly specified for non-turbocharged V6 engines.

Pros:
* – Uses Motorcraft plugs for guaranteed OE quality and fitment.
* – Excellent solution for aging ignition systems (coils often fail around 80k-100k miles).
* – One-year warranty provides buyer confidence.

Cons:
* – Not compatible with the increasingly popular EcoBoost version of the Flex.

Best for: Owners of non-turbocharged Ford Flex models who want to use OEM-spec spark plugs alongside new coil packs.

Expert Opinion: Using Motorcraft plugs removes all guesswork regarding compatibility and performance for standard 3.5L V6 engines. This kit is a reliable, convenient option for a comprehensive maintenance job.

MAS 6Pcs Ignition Coil Pack & 6Pcs Motorcraft Platinum Spark Plug SP520 Compatible with Ford Flex Fusion Lincoln MKS MKZ 3.7 3.5 V6 Replacement for UF553 SP589

Similar to the previous MAS offering, this bundle also features coils and genuine Motorcraft Platinum Spark Plugs (SP520/SP589 equivalent in description text), targeting the naturally aspirated V6 engine (2013-2017 Flex fitment is specifically mentioned). This product reinforces the commitment to providing a complete, high-quality replacement kit that restores factory-level performance and smooth operation.

Key features that stand out:
* Factory-Level Components: Includes Motorcraft SP589/SP520 equivalent plugs.
* Targeted Fitment: Compatible with naturally aspirated 3.5L V6 Flex models (2013-2017).
* Reliable Replacement: Components are designed to replace common OEM part numbers like UF553 and DG520.

Pros:
* – Saves the hassle of sourcing coils and plugs separately.
* – Utilizes widely trusted Motorcraft plug components.
* – Designed to restore factory horsepower and fuel economy.

Cons:
* – Be cautious of potential SP520 vs. SP589 plug confusion in the listing details.

Best for: Flex owners requiring a reliable, complete ignition replacement kit specifically for mid-generation naturally aspirated V6s.

Expert Opinion: It’s wise to replace plugs and coils together, especially on vehicles where component access is difficult, like the Flex. This bundle ensures you get matched parts that work well together right out of the box.

MCK 6pcs Ignition Coil Pack And Motorcraft Iridium Spark Plug Compatible With Ford Lincoln Expedition F-150 F150 Flex Police Interceptor Transit 2011-2017 11-17 3.5L 3.5 V6

MCK offers a compelling upgrade by bundling coil packs with Motorcraft Iridium Spark Plugs. Iridium plugs provide superior heat handling compared to Platinum, which is especially beneficial if your Flex sees heavy use or is an EcoBoost model (though always verify the specific gap). This kit is marketed to provide a “smoother ride” by eliminating common issues like misfires and high fuel consumption immediately after installation.

Key features that stand out:
* Iridium Upgrade: Includes higher-performing Motorcraft Iridium spark plugs.
* Durability Focused: Coils boast excellent heat resistance and corrosion protection.
* Effortless Installation: Designed for a seamless, DIY-friendly replacement process.

Pros:
* – Iridium plugs offer superior performance and lifespan over Platinum.
* – Addresses multiple engine issues (starting, misfires, fuel economy) at once.
* – Direct fitment simplifies the installation process.

Cons:
* – The compatibility description could be clearer regarding naturally aspirated vs. EcoBoost requirement differences.

Best for: Ford Flex owners seeking the longest-lasting, highest-quality component upgrade using Iridium plugs matched with new coils.

Expert Opinion: Pairing Iridium plugs with new coils is often the best combination for maximizing performance and reducing maintenance frequency. If you want a noticeable performance gain and extreme longevity, this is a strong contender.

A-Premium Iridium Platinum Spark Plugs Compatible with Ford F-150, Explorer, Fusion, Transit-150/250/350/350 HD, Taurus, Expedition, Flex, Police Interceptor Sedan/Utility & Lincoln MKZ, Pack of 6

Another excellent dual-metal option from A-Premium, this specific set is tailored for a wide range of later-model Ford 3.5L engines, including the Flex from 2010 to 2019. Similar to their other offerings, this plug features an Iridium tip and Platinum core, optimized for exceptional ignitability and a recommended lifespan of 80,000 to 100,000 miles. Note the specified gap size of 0.032″/0.036″—this smaller gap is crucial for maintaining spark integrity in EcoBoost (turbocharged) engines.

Key features that stand out:
* EcoBoost Friendly Gap: Offers the smaller gap range (0.032″ to 0.036″) often required by turbo engines.
* Dual Precious Metal: Iridium/Platinum construction for maximum performance and wear resistance.
* Longevity Promise: Engineered for replacements between 80,000 and 100,000 miles.

Pros:
* – Excellent option for both naturally aspirated and EcoBoost Flex models (with proper gap verification).
* – Highly durable materials resist electrical arcing and corrosion.
* – Designed to mimic OEM performance specifications closely.

Cons:
* – Gap size must be checked and potentially adjusted depending on the specific Flex engine (NA or EcoBoost).

Best for: Flex owners (especially those with the 3.5L EcoBoost) who require a durable, long-life plug with a tighter, turbo-friendly factory gap.

Expert Opinion: For the EcoBoost engines, the plug gap is critically important. This plug’s specification targeting the 0.032″ range makes it a strong contender for the higher-output turbocharged models, ensuring better spark under high boost pressure.

ECCPP UF553 6 ignition coils with 6 iridium Spark Plugs for ford for Lincoln Edge Flex F150 Explorer Fusion Taurus MKS MKX MKZ CX-9 3.5L 3.7L V6 2007-2017 DG-520 UF553 UF-553

ECCPP provides another strong value proposition with a coil and Iridium spark plug bundle. This kit is built to meet or exceed OE specifications, promising enhanced reliability and superior cold-start performance. They claim that their enhanced coils and plugs provide 15% more energy than the original equipment, helping eliminate frustrating check engine lights and hesitation caused by aged ignition components.

Key features that stand out:
* Iridium Spark Plug Upgrade: Includes durable, high-performance Iridium plugs.
* High Energy Output: Coils are designed to upgrade energy output by 15%.
* Comprehensive Coverage: Fits Flex models from 2009-2017 (3.5L).

Pros:
* – Excellent quality for the price point, covering both plugs and coils.
* – High conductive copper wire ensures superior electrical flow.
* – Addresses common failure symptoms like misfires and poor fuel economy effectively.

Cons:
* – ECCPP components are aftermarket, requiring careful installation to ensure longevity.

Best for: Budget-conscious Flex owners needing to replace both the coils and upgrade to Iridium spark plugs simultaneously.

Expert Opinion: This set is a solid performer for a complete ignition system refresh. The 15% energy upgrade claim is attractive, as improved spark energy directly translates to cleaner, more efficient combustion.

Comparison Short Insights

When evaluating the best spark plugs for Ford Flex, the decision often comes down to budget versus material longevity. If your main goal is long-term, set-it-and-forget-it performance, the Iridium Spark Plugs 6 Pack 97177 or the A-Premium Iridium Platinum options are superior, offering lifespans nearing 100,000 miles.

For maximum convenience and value, especially if your Flex is over 100,000 miles, choosing a coil and plug bundle is highly recommended. The MCK Motorcraft Iridium bundle stands out as it provides the factory-backed quality of Motorcraft Iridium plugs alongside new coils, ensuring a balanced system upgrade.

It’s crucial to note the engine type: the Naturally Aspirated 3.5L V6 can generally use Platinum or standard Iridium plugs (like the Champion Platinum set). However, if you drive the 3.5L EcoBoost (Turbocharged) Ford Flex, you must choose a plug specifically designed for tighter gaps (like the 0.032″ gap found in the A-Premium Iridium Platinum bundle or the 97177 Iridium set) to prevent spark blow-out under boost.

Final Verdict: Which Ford Flex Spark Plugs Should You Buy?

Finding the best spark plugs for Ford Flex really depends on your specific Flex model and your maintenance history. Here are my top three picks based on different needs:

The Factory-Standard Reliability Choice:

For owners of the non-turbo 3.5L V6 (where reliability and factory fit are paramount), the MAS Set of 6 Ignition Coil Pack & 6Pcs Motorcraft Platinum Spark Plug SP589 is the winner. This bundle gives you factory-spec plugs (Motorcraft) and new coils, guaranteeing the smooth operation your Flex had when it was new.

The EcoBoost Performance Choice:

If you own the powerful EcoBoost Flex, you need plugs that can handle the heat and boost pressure. The A-Premium Iridium Platinum Spark Plugs (part number 94374 reference) or the Iridium Spark Plugs 6 Pack 97177 are engineered with the necessary materials and tighter gap specifications to excel in turbocharged environments, preventing misfires when you need power the most.

The Best Budget Tune-Up Choice:

If you need a complete ignition refresh on a tighter budget, the ECCPP UF553 6 ignition coils with 6 iridium Spark Plugs offers unbeatable value. You get the longevity of Iridium plugs combined with a full set of replacement coils, making it a highly practical solution for curing common misfire symptoms without breaking the bank.

Comprehensive FAQs About the Best Spark Plugs for Ford Flex

How often should I replace the spark plugs in my Ford Flex?

The replacement interval depends heavily on the plug material and your engine type. For standard copper plugs (rarely used now), it’s around 30,000 miles. Most modern Iridium or Platinum spark plugs for the Ford Flex 3.5L are rated for replacement between 80,000 to 100,000 miles. Always check your owner’s manual for the specific factory maintenance schedule, especially if you drive an EcoBoost model which may require more frequent checks due to higher demands.

Is there a difference between spark plugs for the naturally aspirated (NA) and EcoBoost Ford Flex 3.5L?

Yes, absolutely. The 3.5L V6 EcoBoost (turbocharged) engine runs higher compression and boost pressure, requiring a smaller spark plug gap (often around 0.032 inches) to prevent the spark from “blowing out” under load. The naturally aspirated 3.5L usually requires a wider gap (around 0.052 inches). Using the wrong gap is a leading cause of misfires in the EcoBoost Flex. Always verify the plug gap against your specific engine model before installation.

What are the main signs that my Ford Flex spark plugs need replacing?

Look out for these common symptoms:
1. Engine Misfires or Rough Idle: The car shakes or hesitates, especially when accelerating.
2. Poor Fuel Economy: A noticeable drop in your gas mileage without changes in driving habits.
3. Difficulty Starting: The engine cranks longer than normal before turning over.
4. Check Engine Light (CEL): Often accompanied by codes related to misfiring in specific cylinders.

Should I replace my ignition coils when I replace the spark plugs?

While not always mandatory, replacing the Ford Flex ignition coils alongside the spark plugs is highly recommended, especially if your vehicle is over 100,000 miles. Since the coil packs sit directly above the plugs and fail over time, replacing them together saves you the labor of having to open the ignition system again in the near future. Bundles like the MAS or MCK kits offer excellent coil and plug value.

Are Platinum or Iridium spark plugs better for my Flex?

Iridium is generally considered the superior material. Iridium alloys have a higher melting point and are six times harder than platinum, resulting in better resistance to electrical erosion and significantly longer lifespan (often 100k+ miles). Platinum plugs are cheaper and offer better performance than standard copper, but if you prioritize maximum spark plug longevity and performance, choose Iridium.

Can old spark plugs cause transmission issues or shaking?

No, old spark plugs don’t directly cause transmission issues. However, severe engine misfires caused by faulty spark plugs can feel like transmission problems (like hesitation or jerking). If the misfires are bad enough, the engine’s computer may limit power or put the vehicle into “limp mode,” which mimics a drivetrain malfunction. Replacing the spark plugs and coils often resolves this perceived issue.