1. Safety First:
* Disconnect the negative battery cable. This prevents accidental shorts and electrical shocks.
* Wear safety glasses. Small parts might fly off during the process.
* Work in a well-ventilated area. Exhaust fumes can be hazardous.
2. Gather Tools and Materials:
* New ignition coil: Make sure you get the correct one for your Expedition's engine (4.6L or 5.4L). The part number is crucial.
* Socket wrench set: You'll need sockets that fit the coil mounting bolts (likely 10mm or 8mm – check your owner's manual or online).
* Ratchet: To turn the socket wrench.
* Extension(s): To reach the coils in tighter spots.
* Wrench (possibly): Some coils might have a retaining clip that requires a small wrench.
* Gloves: To keep your hands clean.
* Shop rags or paper towels: To clean up any spilled oil or grease.
3. Locate the Bad Coil:
* The ignition coils are located on top of the engine, usually one per cylinder. They're typically black rectangular components, often with a single wire connector.
* If you know which cylinder is misfiring (from a diagnostic code or symptoms), you know which coil to replace. If you are unsure, replacing all coils simultaneously may be a better solution, though more expensive.
* Consult your owner's manual or an online diagram to pinpoint the exact location of the coils for your engine.
4. Remove the Bad Coil:
* Disconnect the electrical connector: Carefully unplug the electrical connector from the coil. There might be a locking tab; gently release it.
* Remove the mounting bolts: Use your socket wrench and ratchet to remove the bolts holding the coil in place.
* Remove the coil: Once the bolts are removed, the coil should lift off.
5. Install the New Coil:
* Carefully align the new coil: Make sure it's oriented correctly in the same position as the old one.
* Install the mounting bolts: Tighten them securely but don't overtighten.
* Reconnect the electrical connector: Ensure it's securely plugged in.
6. Reconnect the Battery and Test:
* Reconnect the negative battery cable.
* Start the engine: Listen for any changes in engine noise or running. A smoother idle indicates a successful repair.
* Test drive: Take the Expedition for a test drive to ensure the misfire is resolved.
Important Considerations:
* Misfire diagnosis: If you haven't already identified the misfiring cylinder, get your vehicle diagnosed professionally. Replacing coils without knowing which one is faulty is costly and inefficient. A simple OBD-II scanner can often reveal misfire codes.
* Spark plug condition: A faulty spark plug can damage a coil. Consider replacing the spark plug in the corresponding cylinder while you're at it.
* Professional help: If you're not comfortable working on your vehicle, take it to a qualified mechanic. Improper repair can lead to further damage.
This guide provides general steps. Specifics may vary slightly depending on your Expedition's exact engine and configuration. Always consult your owner's manual or a repair manual specific to your vehicle year and engine for detailed instructions and diagrams. YouTube videos demonstrating this repair on a similar year and model Ford Expedition can also be extremely helpful.
