2019 Ford Ranger Spark Plug Type & Gap

Quick Reference

Why the Right Plug Matters

Modern engines like the 2.3L EcoBoost in your 2019 Ranger are highly sophisticated, relying on precise control over combustion to deliver their impressive blend of power and efficiency. The spark plug is at the heart of this process, and using the correct one is critical for engine health, performance, and longevity. The original equipment (OEM) plug is a fine-wire iridium-tipped unit, chosen for specific reasons.

• Heat Range: This is the most critical factor. A spark plug must get hot enough to burn off carbon deposits for a clean firing surface, but not so hot that it causes pre-ignition (detonation), which can severely damage an engine. Turbocharged, direct-injection engines like the EcoBoost run higher cylinder pressures and temperatures, requiring a "colder" plug that dissipates heat quickly.
• Electrode Material: The move from traditional copper plugs to precious metals like platinum and iridium is all about durability. Iridium has an extremely high melting point and is incredibly hard, allowing manufacturers to use a very fine center electrode. This requires less voltage to create a spark, provides a more focused and consistent spark kernel, and resists erosion for a much longer time. While copper is an excellent conductor, it wears out far too quickly for a modern engine with a 100,000-mile service interval.

How to Gap a Spark Plug

Even though iridium plugs are pre-gapped from the factory, it is always best practice to verify the gap before installation. Shipping and handling can easily close the gap.

1. Use the Right Tool: Use a dedicated wire-loop or feeler gauge tool. Do not use the cheap "coin-style" gapping tools, as they can put pressure on the fragile fine-wire electrode and damage it.
2. Measure Carefully: For the 2.3L EcoBoost, the gap should be between 0.028 and 0.031 inches (0.7-0.8 mm). Slide the correct wire or feeler gauge between the center and ground electrodes. It should pass through with a slight drag. If it's too loose or won't fit, the gap needs adjustment.
3. Adjust Gently: To adjust, never pry against the center electrode. Instead, gently bend the ground strap (the J-shaped hook over the top) by leveraging the gapping tool against the top of the plug body. Make tiny adjustments and re-measure until it's perfect.

Replacement Procedure Tips

The 2019 Ranger uses a modern and straightforward coil-on-plug ignition system.

• Coil-on-Plug Removal: Each spark plug has its own ignition coil sitting directly on top of it. To access the plug, first disconnect the electrical connector from the coil. Then, unbolt the single hold-down bolt (typically 8mm). The coil can then be gently twisted and pulled straight up. If it feels stuck, do not yank on it; a slight twisting motion will help break the seal between the boot and the plug porcelain.
• The Anti-Seize Debate: This is a hot topic. Ford and plug manufacturers like NGK officially recommend not using anti-seize compound on the threads of modern plated plugs (like the nickel-plated OEM plugs). The plating itself provides sufficient corrosion resistance and the correct lubricity. Applying anti-seize can act as a lubricant, leading you to inadvertently over-torque the plug, which can stretch the threads in the aluminum cylinder head or damage the plug itself.
• Dielectric Grease: A small amount of dielectric grease applied to the inside of the coil boot (not on the metal terminal itself) is highly recommended. This prevents the boot from getting stuck to the spark plug porcelain over time and helps seal out moisture, preventing corrosion.

Known Issues

Fortunately, the 2.3L EcoBoost engine in the 2019 Ranger is not associated with the major spark plug issues that plagued some earlier Ford engines. The infamous Ford 3-valve Triton engine (e.g., 5.4L V8) used a two-piece spark plug shell design that was notorious for breaking apart during removal, leaving the lower portion seized in the cylinder head. The plugs used in your Ranger are a conventional one-piece design and do not share this problem.

Regularly scheduled replacement with the correct, properly gapped and torqued spark plugs will ensure your Ranger continues to perform as designed for many miles to come.

Need plugs replaced? Find a shop on Repairius.