Is your engine stuttering or guzzling gas? I tested Motorcraft and Autolite spark plugs in my 2007 Ford Mustang GT to find the best fit. This article shares my real-world experience, key features, pros, cons, and a head-to-head comparison to help you decide.

With a conversational vibe, I’ll break down what worked, what didn’t, and how to make your engine purr. Grab a set of either and let’s find out which plug powers your car better!

Motorcraft vs. Autolite: Comparison Table

My Journey with Motorcraft and Autolite Spark Plugs

My 2007 Ford Mustang GT, a 4.6L V8 beast, started acting up last summer—rough idling, a misfire on cylinder 3, and a check-engine light flashing code P0303.

I knew the spark plugs were due for a swap, so I decided to pit Motorcraft against Autolite to settle the debate.

Over eight months and 9,000 miles, I tested Motorcraft SP-515 double platinum plugs and Autolite XP104 iridium plugs, swapping halfway to compare.

I installed them in my garage with a torque wrench and anti-seize, and the results were eye-opening. Here’s how it went down.

First up were the Motorcraft SP-515 plugs. They’re Ford’s OEM choice, so I expected perfection. After a 45-minute install, my Mustang roared back—smooth idle, crisp acceleration, and no more misfires. Fuel economy jumped from 16 to 17 MPG in city driving. But at $12 a plug, they stung my wallet.

Then I swapped to Autolite XP104 iridiums. They were half the price and just as easy to install. The idle was even smoother, and I gained another 0.5 MPG. Both brands delivered, but each had quirks. Let’s break it down.

• Instant Fix: Motorcraft plugs killed the misfire immediately, restoring my Mustang’s growl.
• Fuel Efficiency: Autolite edged out with a 0.5 MPG boost over Motorcraft, saving $6 per tank.
• Smooth Idle: Autolite’s iridium tip gave a silkier idle, noticeable at stoplights.
• Installation Ease: Both were plug-and-play, done in under an hour with basic tools.
• Towing Performance: Motorcraft shone when hauling my 1,500-pound trailer, feeling punchier.
• Cost Savings: Autolite’s $6 per plug vs. Motorcraft’s $12 saved me $48 for eight.
• Weather Resilience: Autolite handled humid summer drives better; Motorcraft stumbled slightly.
• Gap Retention: Autolite’s gap held steady at 0.054 inches; Motorcraft widened slightly.
• Power Delivery: Motorcraft’s OEM tuning gave better high-RPM performance.
• No Codes: Both cleared P0303, and no misfire codes returned in 9,000 miles.

Key Features Of Motorcraft Spark Plugs

Motorcraft, Ford’s OEM parts brand since 1972, is built for Ford engines like my Mustang’s 4.6L. The SP-515 double platinum plugs I used are designed for modular V8s, with a focus on reliability and Ford-specific tuning. They’re made by Autolite (now under FRAM Group) to Ford’s exact specs, ensuring a perfect fit.

• OEM Precision: Engineered for Ford’s modular engines, ensuring seamless integration.
• Double Platinum Design: Platinum on both electrodes extends life up to 100,000 miles.
• Anti-Corrosion Coating: Nickel-plated shell resists rust, ideal for coastal drives.
• Heat Range Accuracy: Optimized for Ford’s 4.6L and 5.4L, reducing pre-ignition.
• Fine-Wire Electrode: Delivers a strong, consistent spark for smooth combustion.
• Wide Compatibility: Fits most Ford models, some GM, and select other makes.
• Durable Ceramic: High-quality insulator resists cracking, even in hot engines.
• Pre-Gapped: Set at 0.054 inches for my Mustang, saving installation time.
• Ford-Backed Warranty: 2-5 years, offering confidence in OEM reliability.
• Performance Tuning: Boosts acceleration, especially in high-RPM scenarios.

Key Features Of Autolite Spark Plugs

Autolite, around since 1936, started as a Ford supplier before becoming an aftermarket giant. Their XP104 iridium plugs, which I tested, use a 0.6mm fine-wire electrode for quick ignition and efficiency. They’re built for versatility, fitting Fords, GMs, and imports.

• Iridium Fine-Wire: 0.6mm tip ensures a precise spark, boosting fuel economy.
• Platinum Sidewire: Protects ground electrode, extending life to 100,000 miles.
• Cooler Operation: Dissipates heat fast, preventing pre-ignition in V8s.
• Nickel-Plated Shell: Resists corrosion, holding up in wet or salty conditions.
• Pre-Gapped Design: Set at 0.054 inches, making installation a breeze.
• Broad Compatibility: Fits Ford, GM, Chrysler, and many import vehicles.
• Fuel Efficiency Focus: Optimized spark improves MPG, ideal for daily drivers.
• Affordable Premium: Iridium plugs at $6-$8 offer high-end performance for less.
• Racing Heritage: Used by top fuel teams, adding street cred for enthusiasts.
• Reliable Warranty: 2-5 years, competitive for aftermarket plugs.

Pros Of Motorcraft Spark Plugs

Motorcraft plugs felt like they were made for my Mustang, which makes sense—they’re Ford’s OEM choice.

Here’s why they’re a solid pick:

• OEM Reliability: Tuned for Ford engines, they eliminated misfires instantly.
• Smooth High-RPM Performance: Shined during spirited drives, hitting 5,000 RPM easily.
• Long Lifespan: Double platinum design lasts up to 100,000 miles with care.
• Perfect Fitment: No guesswork; SP-515s were exact matches for my 4.6L.
• Anti-Corrosion Build: Nickel plating held up in humid, salty air.
• Strong Towing Power: Handled my 1,500-pound trailer without breaking a sweat.
• Consistent Spark: No misfires or codes over 4,500 miles of testing.
• Ford-Backed Quality: Built to Ford’s specs, ensuring top-tier performance.
• Wide Availability: Found at Ford dealers and most auto parts stores.
• Durable Insulator: Ceramic resisted cracking, even in my hot-running V8.

Cons Of Motorcraft Spark Plugs

Motorcraft wasn’t flawless, and a few issues annoyed me:

• Pricey: At $12 per plug, they cost twice as much as Autolite’s iridiums.
• Humidity Sensitivity: Slight hesitation in muggy weather, unlike Autolite.
• Gap Wear: After 4,500 miles, the gap widened to 0.058 inches, affecting idle.
• Limited Non-Ford Fit: Less versatile for non-Ford vehicles compared to Autolite.
• Dealer Markup: Ford dealers charged $20 per plug, way more than online.
• No Copper Options: Lacks budget-friendly copper plugs for older engines.
• Slightly Rough Idle: Not as smooth as Autolite at low RPMs.
• Rare Defects: Some users report cracked ceramics, though mine were fine.
• Less Fuel Efficiency: Lagged behind Autolite by 0.5 MPG in city driving.
• Specificity Issues: Vague part numbers led to ordering confusion online.

Pros Of Autolite Spark Plugs

Autolite plugs surprised me with their performance and price. Here’s why they’re worth your attention:

• Budget-Friendly: At $6 per plug, I saved $48 over Motorcraft for eight.
• Silky Idle: Iridium tip gave a smoother idle than Motorcraft, especially at stoplights.
• Fuel Savings: Boosted MPG by 0.5, saving $6 per tank on my commute.
• Weather Resilience: No hesitation in humid or hot conditions, unlike Motorcraft.
• Long-Lasting Iridium: Rated for 100,000 miles, perfect for long-term use.
• Versatile Fitment: Fits Fords, GMs, and imports, great for multi-car owners.
• Cooler Running: Reduced pre-ignition risks in my hot 4.6L engine.
• Easy Installation: Pre-gapped and plug-and-play, done in 45 minutes.
• Strong Reputation: Trusted in racing and aftermarket, with solid reviews.
• Corrosion Resistance: Nickel plating held up in wet winter conditions.

Also read:My Final Thoughts The Spectre Air Filters

Cons Of Autolite Spark Plugs

Autolite had some downsides I couldn’t ignore:

• Weaker Towing Performance: Less punch than Motorcraft when towing heavy loads.
• Shorter Warranty: 2-5 years matches Motorcraft but feels less reassuring.
• Fitment Confusion: Listings were vague, nearly causing a wrong purchase.
• Not OEM-Tuned: Slightly less optimized for Ford’s modular engines.
• Occasional Defects: Rare reports of cracked porcelains, though mine were solid.
• Limited Copper Range: Fewer budget copper options compared to other brands.
• Availability Issues: Some stores lacked specific iridium models, forcing online orders.
• Less High-RPM Power: Not as strong as Motorcraft at 5,000+ RPM.
• Mixed Racing Fit: Underperformed in high-performance setups vs. OEM.
• Slight Noise: One plug buzzed faintly under load, but performance was fine.

Motorcraft Vs. Autolite: Head-To-Head Comparison

I compared Motorcraft and Autolite across key metrics based on my Mustang tests and research. Here’s the breakdown.

Performance

• Motorcraft: OEM tuning gave a crisp, high-RPM performance, perfect for spirited drives. Towing felt effortless, but humid weather caused slight stumbles.
• Autolite: Smoother idle and consistent spark in daily driving. Less punchy when towing but held steady in all weather conditions.

Durability

• Motorcraft: Double platinum lasts up to 100,000 miles, but gap widened slightly after 4,500 miles.
• Autolite: Iridium also hits 100,000 miles, with better gap retention in my tests.

Price

• Motorcraft: $12-$20 per plug is steep; $96 for eight hurt my wallet.
• Autolite: $6-$8 per plug ($48 for eight) offers premium performance for less.

Installation

• Motorcraft: Plug-and-play, but vague part numbers caused ordering mix-ups.
• Autolite: Pre-gapped and easy, though listings could be clearer.

Fuel Efficiency

• Motorcraft: Improved MPG from 16 to 17, solid but not spectacular.
• Autolite: Pushed MPG to 17.5, saving more fuel on my daily commute.

Compatibility

• Motorcraft: Perfect for Ford’s modular engines, less versatile for non-Fords.
• Autolite: Fits a wider range, including Fords, GMs, and imports.

Warranty

• Motorcraft: 2-5 years, backed by Ford’s OEM reputation.
• Autolite: 2-5 years, competitive but lacks Ford’s OEM clout.

Reputation

• Motorcraft: Ford’s go-to, with strong OEM reliability but pricier.
• Autolite: Trusted aftermarket choice, especially for Ford owners, with fewer complaints.

Also read:My Final Thoughts The Spectre Air Filters

Tips To Get The Most Out Of Your Spark Plugs

To keep Motorcraft or Autolite plugs firing strong, I learned these tricks over eight months:

• Apply Anti-Seize: Use nickel anti-seize on threads to prevent seizing in aluminum heads.
• Verify Gaps: Check gaps (0.054 inches for my Mustang) before installing for optimal spark.
• Pair with Quality Coils: I used Carbole coils for consistent spark delivery.
• Replace All Plugs: Swap all eight plugs together for even cylinder performance.
• Clean Connectors: Rubbing alcohol on boots ensures a tight electrical connection.
• Torque Correctly: Tighten to 11-15 ft-lbs to avoid damaging threads or ceramics.
• Monitor Weather: Check Motorcraft plugs in humidity; Autolite handles it better.
• Inspect Every 15,000 Miles: Look for wear or fouling, especially on platinum plugs.
• Match OEM Specs: Use SP-515 or XP104 for Ford V8s to avoid fitment issues.
• Store Spares Safely: Keep extra plugs in a cool, dry place to prevent damage.

Frequently Asked Questions (FAQ)

Conclusion

After eight months testing Motorcraft and Autolite spark plugs in my Mustang, both impressed me.

Motorcraft’s OEM tuning delivers for high-RPM drives and towing, but Autolite’s smoother idle and fuel savings stole the show for daily driving.

At half the price, Autolite’s my pick for value. Grab either, follow my tips, and keep your engine roaring!