Ford Ignition Coils and Spark Plugs: Matching the Pair to Your Engine

Most modern Ford engines have a separate ignition coil for each cylinder, sitting directly on top of the spark plug. The coil turns the 12 volts from the battery into the high voltage that makes the plug spark. The plug and the coil work as a pair: a worn plug makes the coil work harder, and a weak coil can cause a misfire even with a good plug.

We cover spark plug intervals and the general causes of misfires in our guide When to Replace Spark Plugs and How to Stop Engine Misfires. This article focuses on ignition coils and on choosing the right plug and coil pair for your Ford engine.

Coil or Plug? The Symptoms

• The engine shakes at idle or at traffic lights
• The car jerks or hesitates when accelerating or climbing a hill
• The Check Engine light is on; if it is flashing, the engine is actively misfiring - reduce the load and have it checked soon, because unburned fuel can damage the catalytic converter
• Fuel consumption has gone up
• The misfire gets worse in damp or rainy weather - this often points to a cracked coil boot or coil body

How to Tell Them Apart

1. Read the fault codes. A scanner shows which cylinder is misfiring: P0301 is cylinder 1, P0302 is cylinder 2, and so on. P0300 means random misfires in several cylinders.
2. Swap the coil. Move the coil from the misfiring cylinder to another one and clear the codes. If the misfire follows the coil, the coil is faulty. If it stays in the same cylinder, check the plug, the injector or the compression.
3. Inspect the plug. Look for a worn electrode, oil or carbon deposits, or a cracked insulator.
4. Inspect the coil boot. Look for cracks, burn marks, or oil or water in the spark plug well.

Replace Together or One by One?

• Spark plugs are always replaced as a full set - all cylinders at once.
• Coils are usually replaced one at a time when one fails. On a high-mileage car where coils fail one after another, many owners replace the whole set.
• When you replace the plugs, check the coil boots as well.
• Use the plug specified for your engine and tighten it to the torque the manufacturer specifies.

Plug and Coil by Ford Engine

Ford uses the same displacement in different engines: a 2.0 can be naturally aspirated or EcoBoost, and a 3.5 can also be either. They take different spark plugs, so choose by engine and year and confirm by VIN.

The 3.5 appears in both lists: whether your 3.5 is an EcoBoost or not decides which plug it takes. If you cannot find the coil for your engine in the catalog, send us a request with your VIN.

Parts by model: Engine parts · Ford Escape · Ford Fusion · Ford Explorer · Ford F-150

Not sure which plug or coil you need? Send us a part request with your VIN, or call or message us on WhatsApp: +995 505 05 06 51. We work every day, 10:00-19:00.