By Lund Racing — The World Leader in Ford & Coyote Tuning
Your spark plugs are the final step in the combustion command chain — the last link between optimal performance, a powerful tune, and maximum horsepower. Whether you're running 11s on drag radials or towing heavy loads in your F-150, spark plug health is critical to the optimal performance outcome of the vehicle.
For 2011+ Ford 5.0L Coyote-powered vehicles — including the S197/S550 Mustang GTs and F-150s — spark plug maintenance plays a key role in engine longevity, fuel economy, and most importantly, performance under boost or load.
Gapping your spark plugs should only be done with the latest in spark plug gapping tools to prevent damage to the plug itself.
Why You Need Colder Spark Plugs for Boost
Here’s the core principle: More power = more heat. A spark plug’s heat range indicates its ability to dissipate heat from the combustion chamber. “Hot” plugs retain more heat, while “cold” plugs transfer it away faster. It’s not about how hot the spark is—it's about how the plug manages (dissipates) heat after combustion. When combustion chamber temperatures rise due to higher cylinder pressures (from boost or aggressive timing), hotter spark plugs can’t dissipate the excess heat fast enough. This can lead to:
Pre-ignition - when the air/fuel mixture ignites before the spark fires
Detonation/knock - uncontrolled combustion
Spark plug electrode degradation or even melting
Engine damage in worst-case scenarios
Running a colder spark plug helps prevent these issues by reducing the risk of the plug itself becoming a hot spot. Once you start pushing more horsepower—especially through forced induction (turbo or supercharger) or aggressive naturally aspirated tuning—you’re also increasing combustion temperatures. Higher temps require better thermal management, and that’s where colder plugs come into the equation. There may be instances where a 1000hp setup may need to go even colder on their plug selection (over the suggested NGK6510), due to their setup being inefficient somewhere in the combo where they're enduring exceptionally high Inlet Air Temps (IATs).
Modern spark plugs being installed into the Coyote platform engines should not utilize any Anti-Seize, either. This is an outdated practice and not warranted on modern plugs as most aftermarket plug manufacturers utilize a zinc-based coating on the threads of their plugs to prevent corrosion. The addition or use of Anti-Seize can actually cause invalid torque numbers when tightening and even impact the heat range of the spark plug - which we want total control over.
Quick Reference: Spark Plug Recommendations by Vehicle & Year
*Editor's Note: NGK6509 / LTR6IX-11 = Stock Heat Range. NGK6510 / LTR7IX-11 = 1 Step Colder. Brisk RR12s = 2 Steps Colder. Brisk RR10s = 3 Steps Colder. Brisk RR08s = 4 Steps Colder.
| Model | Engine | OEM Plug | Aftermarket (N/A) | Aftermarket (Boosted) | Boosted 1000-1100hp | Boosted 1100-1500hp | Boosted 1500-2000hp |
| Mustang GT | Gen 1 Coyote (11-14) | SP534 / CYFS-12YTC | NGK6509 (LTR6IX-11) | NGK6510 (LTR7IX-11) or Brisk RR12S | NGK6510 or R7448A8 | R7448A-9 or Brisk RR12S | R7448A-10 or Brisk RR10S |
| Gen 2 Coyote (15-17) | SP542 (SP534 Equivalent) | NGK6509 (LTR6IX-11) | NGK6510 (LTR7IX-11) or Brisk RR12S | NGK6510 or R7448A8 | R7448A-9 or Brisk RR12S | R7448A-10 or Brisk RR10S | |
| Gen 3 Coyote (18-23) | SP578 / CYFS-12YTCA | NGK6509 (LTR6IX-11) | NGK6510 (LTR7IX-11) or Brisk RR12S | NGK6510 or R7448A8 | R7448A-9 or Brisk RR12S | R7448A-10 or Brisk RR10S | |
| F150 5.0L | Gen 1-3 Coyote (11-20) | SP534 / CYFS-12YTC | NGK6509 (LTR6IX-11) | NGK6510 (LTR7IX-11) or Brisk RR12S | NGK6510 or R7448A8 | R7448A-9 or Brisk RR12S | R7448A-10 or Brisk RR10S |
| Gen 4 Coyote (21+) | SP594 / CYFS-12-F1A | SP594 / CYFS-12-F1A | M12405-50VDE or Brisk XER10s | Contact Lund Racing! | Contact Lund Racing! | Contact Lund Racing! |
📌 Note: Boosted vehicles should be inspecting your spark plugs before and after every race/event as well as at every oil change service interval. Regularly inspecting & keeping a consistent gap is crucial to optimal performance on your boosted vehicles.
⚠️ Pro Tip: Boosted vehicles making above 18psi should consult with your Calibrator in your Tuning Ticket to confirm spark plug recommendations. These will oftentimes be Brisk RR12s, BriskRR10s or NGKR7448As & we typically suggest keeping a set of NGK6510s on-hand for cold-starts and/or street use in these instances (more on this below).
🔧 21+ F150 Note: The 2021+ F150 introduced the Gen 4 engine platform which uses the updated SP-594 (Motorcraft CYFS-12-F1A) plug, and has a factory-set .030" gap, which is considerably tighter than previous years & is no longer compatible with the aforementioned NGK6509 / NGK6510 spark plugs.
When to Replace Spark Plugs
| Driving Style | N/A Application | Forced Induction |
| Daily Driving | 40,000-60,000 miles | 15,000-20,000 miles |
| Spirited/Track | 30,000-40,000 miles | 10,000-15,000 miles |
| Heavy Towing (F150) | 25,000-30,000 miles | 10,000-12,000 miles |
📌 Tip: For Lund-tuned vehicles, always inspect your spark plugs before your first datalogs are requested by your Calibrator.
⚠️ Tip: For Lund-tuned Boosted applications you should start out with a slightly tighter gap (.026"–.028"), and we may advise you to go even tighter, depending on boost levels. For instance, we've tested the NGK6510s down to the .020"-.022" gap with success & the Brisks we've run even tighter in many instances.
As a rule of thumb, we advise our customers who have moved on to Brisk RR12s (or colder) to make sure you keep a set of "Trailer Plugs" (as we lovingly call them), which should be utilized for cold start situations, getting the engine up to operating temp, and/or street driving duties (as necessary). You need to understand the colder nature of the 2-step colder plugs will cause them to foul out in a much sooner manner in these aforementioned conditions, as such you'll want to keep a fresh set of NGK6510s on-hand to rotate in and out for these situations as a best practice to increase the life and longevity of your colder plugs. It would be prudent to add this step to your pre-race & post-race checklists, as well.
🔧 Pro Tip: If you're actively using the vehicle to race, you should always have at least one spare set of pre-gapped plugs in the vehicle ready to swap into the vehicle at a moment's notice. This is especially true for higher horsepower applications, race days, dyno days, etc.
How to Inspect Your Spark Plugs: Visual Diagnosis
Pull a plug and read it. Here's what to visually look for along with the most common issues that would lead to the plug looking that way:
Tan/Grey Insulator: Normal burn
Black Sooty Tip: Rich fuel mixture or bad combustion event
White Tip/Bubbled Electrode: Lean condition or detonation
Oil Fouling: Possible valve seal, PCV, or ring issue
Worn Electrode: Overdue for replacement, potential misfire
Rust/Orange Tip: Oftentimes from use of an Octane Booster / Additive
Cracked Ceramic: Overtightening or PTV impact
⚠️ Note: the more Ethanol Content you run (or Pure Methanol use) the harder the plugs will be to read according to these visual inspection notes!
Common CELs & DTCs Related to Spark Plugs
If you’re scanning your Coyote-powered Mustang or F-150, the following codes often point to spark plug issues:
| DTC Code | Description |
| P0300 | Random/Multiple Cylinder Misfire Detected |
| P0301 | Misfire in Cylinder 1 |
| P0302 | Misfire in Cylinder 2 |
| P0303 | Misfire in Cylinder 3 |
| P0304 | Misfire in Cylinder 4 |
| P0305 | Misfire in Cylinder 5 |
| P0306 | Misfire in Cylinder 6 |
| P0307 | Misfire in Cylinder 7 |
| P0308 | Misfire in Cylinder 8 |
| P0316 | Misfire Detected on Startup |
| P0171 | System Too Lean - Bank 1 |
| P0172 | System Too Rich - Bank 1 |
| P0174 | System Too Lean - Bank 2 |
| P0175 | System Too Rich - Bank 2 |
| P0351 | Ignition Coil Primary/Secondary Circuit Malfunction (Cyl 1) |
| P0352 | Ignition Coil Primary/Secondary Circuit Malfunction (Cyl 2) |
| P0353 | Ignition Coil Primary/Secondary Circuit Malfunction (Cyl 3) |
| P0354 | Ignition Coil Primary/Secondary Circuit Malfunction (Cyl 4) |
| P0355 | Ignition Coil Primary/Secondary Circuit Malfunction (Cyl 5) |
| P0356 | Ignition Coil Primary/Secondary Circuit Malfunction (Cyl 6) |
| P0357 | Ignition Coil Primary/Secondary Circuit Malfunction (Cyl 7) |
| P0358 | Ignition Coil Primary/Secondary Circuit Malfunction (Cyl 8) |
Don't Guess — Scan First! Inspect Next!
If you're experiencing misfires at idle, hesitation under load, or a rough cold start, don't guess - scan the vehicle for DTC Codes. If you find any of the aforementioned P-Codes which could be related to the plugs having an issue, then you need to pull those plugs! They’re cheap insurance compared to the cost of melted pistons or damaged/failed O2 sensors from detonation.
How to Change Spark Plugs on the 5.0L Coyote
Tools Required:
5/8" magnetic spark plug socket in 1/2" drive
1/2" to 3/8" drive reducer
(2) 3/8" extensions 3" long
8mm socket for coil packs
Trim removal tool for harness/clips
Torque wrench (set to 133 in-lbs / ~11 ft-lbs)
Dielectric grease for coil boots
- NOTE: ANTI-SEIZE WAS NOT MENTIONED & FOR GOOD REASON!
Steps:
Let engine cool completely (spark plug threads in aluminum heads can strip when hot).
Disconnect negative battery terminal.
Remove coil packs (1 bolt each, 8mm).
Blow out spark plug well with compressed air.
Carefully remove spark plugs.
- Prepare the magnetic spark plug socket, 1/2" to 3/8" reducer & the (2) 3" extensions to utilize as a breakable/removable combo to gain access to the #4 spark plug with ease (passenger side, rear, closest to firewall).
Double check all spark plug gaps before installing (even pre-gapped plugs can be off).
- Install new plugs and torque correctly.
Reinstall coils with a very small dab of dielectric grease in the boots.
Conclusion: Dialed in from Street to Strip
At Lund Racing, we’ve calibrated thousands of Coyotes and understand how critical a proper plug setup is — especially on high-horsepower or forced-induction builds.
The right spark plug setup ensures you're not leaving power on the table — or risking damage. Whether you're towing, racing, or just carving corners on a mountain pass, we’ve got your tune — and now, your plug guide — dialed in.
📦 Need Plugs or Install Help?
Check out our authorized dealers to purchase your NGK, Brisk or Ford Motorcraft spark plugs. They're also usually available to provide installation for you, too. As always, contact Lund Racing's Support Team for personalized recommendations based on your tune and your specific setup if it's not been covered here in this tech article:
Email Support: support@lundracing.com
Tuning Support: www.lundracing.com/support
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