Spark Plug Replacement
ModerateSpark plug replacement involves removing the old spark plugs and installing new ones gapped to the correct specification. Spark plugs ignite the air-fuel mixture in each cylinder. Worn plugs cause misfires, rough idling, poor fuel economy, and difficulty starting the engine.
Estimated time: 1-2 hours
Cost Breakdown
DIY (Parts Only)
$50 - $200
Professional Shop
$150 - $500
Prices vary by location, vehicle make/model, and shop rates.
Tools Needed
- Spark plug socket
- Socket wrench set
- Torque wrench
- Gap gauge
- Dielectric grease
Step-by-Step Instructions
Allow the engine to cool completely. Remove the engine cover if equipped.
Disconnect the ignition coil connector and remove the ignition coil or spark plug wire from the first cylinder.
Use compressed air or a brush to clean debris away from the spark plug well to prevent it from falling into the cylinder.
Remove the old spark plug using a spark plug socket and ratchet. Inspect the electrode for wear patterns.
Check the gap on the new spark plug with a gap gauge and adjust if needed to match manufacturer specifications.
Thread the new spark plug in by hand first to avoid cross-threading, then torque to the manufacturer's specification.
Reinstall the ignition coil or plug wire, apply dielectric grease to the boot, and repeat for all remaining cylinders.
Tips & Warnings
- Never install spark plugs on a hot engine — the threads can strip in the aluminum cylinder head.
- Use anti-seize compound on the threads only if recommended by the plug manufacturer (some platinum/iridium plugs come pre-coated).
- Replace all spark plugs at once even if only one appears worn to maintain balanced combustion.
- Inspect the ignition coils and plug wires while you have access — cracked boots should be replaced.
Related OBD-II Codes
Related Recalls
1 Active Recall — 2026 Ford F-150
The following NHTSA safety recalls have been issued for this vehicle. Contact your dealer to check if your vehicle is affected.
ELECTRICAL SYSTEM: INTEGRATED TRAILER BRAKE CONTROL
Ford Motor Company (Ford) is recalling certain 2021-2026 F-150, 2022-2026 F-250 SD, F-350 SD, F-450 SD, F-550 SD, Maverick, 2024-2026 Ranger, 2023-2026 F-600 SD, 2022-2027 Lincoln Navigator, Expedition, and 2026 E-Transit vehicles. When towing a trailer, the integrated trailer module (ITRM) may lose communication with the vehicle, possibly causing a loss of brake and turn signal lights, or a loss of brake function. As such, these vehicles fail to comply with the requirements of Federal Motor Vehicle Safety Standard number 108, " Lamps, Reflective Devices, and Associated Equipment."
Remedy: The integrated trailer module software will be updated by a dealer, or through an over-the-air (OTA) update, free of charge. Owner notification letters are expected to be mailed March 17, 2026. Owners may contact Ford customer service at 1-866-436-7332. Ford's number for this recall is 26C10. Vehicle Identification Numbers (VINs) involved in this recall will be searchable on NHTSA.gov beginning March 17, 2026.
Data provided by the National Highway Traffic Safety Administration (NHTSA).
Recommended Parts & Tools
spark plug replacement
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