Ignition Coil and Iridium Spark Plugs for Ford Expedition (2018-2021) 3.5L

High-Output Ignition Coil and Iridium Spark Plugs for 2018-2021 Ford Expedition (U553)

What it Does: The Ignition Coil and Iridium Spark Plugs kit restores secondary ignition voltage and combustion stability across all cylinders on the 2018-2021 Ford Expedition to eliminate misfires under heavy boost.

The Stock Ford Expedition Ignition System Weakness

The twin-turbocharged direct-injected 3.5L EcoBoost engine subjects primary and secondary ignition components to intense thermal stress and elevated cylinder pressures. Over time, high combustion pressures increase the resistance required to jump the spark gap. The factory coil-on-plug (COP) assemblies suffer from dielectric degradation within the internal epoxy windings and thermal fatigue in the silicone boots. Under load or boost ramp-up, weak spark discharge leads to spark blowout, hesitations, diminished fuel efficiency, and standard cylinder misfire diagnostic trouble codes (P0300–P0306).

The Engineering Solution

This complete tune-up kit resolves high-load misfires by matching six high-dielectric epoxy-filled ignition coils with fine-wire iridium spark plugs. The coils feature heat-resistant silicone boots, copper core windings, and factory 3-blade electrical terminals designed to withstand severe thermal cycling. The paired iridium plugs utilize a laser-welded fine-wire center electrode that lowers the required strike voltage and exhibits superior erosion resistance compared to standard copper or platinum alternatives, ensuring reliable spark kernel propagation under maximum twin-turbo boost.

What's Included

• 6 Black Ignition Coils (3-Blade Connector)
• 6 Iridium Spark Plugs

Technical Specifications

Compatibility

• 2018-2021 Ford Expedition 3.5L V6 Twin Turbo EcoBoost (Standard and MAX Chassis; XLT, Limited, King Ranch, Platinum)

Frequently Asked Questions & Fitment Warnings

Does this fit the U553 Expedition?

Yes, this is a direct fit for the 2018-2021 Ford Expedition equipped with the 3.5L EcoBoost Gen 2 engine. This kit does not fit 2015-2017 first-generation 3.5L EcoBoost engines due to coil mounting and connector differences.

Do I need dielectric grease during installation?

Applying a thin film of dielectric grease to the interior lip of the boots ensures complete moisture sealing and prevents thermal boot adhesion to the spark plug ceramic body.

The Ford Heavy-Duty Standard

Moving a full-size SUV under heavy payload or gross trailer weight requires uninterrupted low-end torque. This direct ignition overhaul guarantees reliable flame propagation and complete fuel atomization to sustain maximum towing capability without detonation or misfires.