Ignition Coil and Iridium Spark Plugs for GMC Envoy XUV (2004-2005) 4.2L

Direct-Fit Ignition Coil and Iridium Spark Plug Kit for 2004-2005 GMC Envoy XUV

What it Does: The ignition coil and iridium spark plug kit restores secondary ignition voltage and combustion efficiency on the 2004-2005 GMC Envoy XUV to eliminate misfires, stabilize idle, and recover lost engine power.

The Stock GMC Envoy XUV Coil Breakdown and Voltage Leakage

Factory ignition coils on the GMT360 platform paired with the LL8 4.2L inline-six are exposed to extreme thermal cycles within deep cylinder head wells. Over time, heat soak degrades the factory internal epoxy and silicone boots, creating dielectric breakdown, secondary voltage leaks, and spark blowout under load. Worn factory plugs increase electrode resistance, which overworks primary coil windings and precipitates erratic P0300 misfire codes, unburned fuel entering the catalytic converter, and noticeable hesitation during acceleration.

The Engineering Solution

This replacement ignition kit pairs high-dielectric insulated pencil coils with fine-wire iridium spark plugs to establish consistent spark duration and complete fuel burn. The coil packs feature high-grade magnetic copper windings encased in reinforced potting resin to resist thermal cracking and dielectric puncture. The matched iridium plugs utilize laser-welded center electrodes that require lower strike voltages, reducing electrical load across the circuit. Built to direct-fit interchange specifications UF303 and 68070492AB, this setup restores quick cold starts, precise combustion timing, and steady idle stability without harness modification.

Technical Specifications

Compatibility

• 2004 GMC Envoy XUV (4.2L I6 LL8)
• 2005 GMC Envoy XUV (4.2L I6 LL8)
• Fits SLE and SLT trim packages equipped with the 4.2L inline-six engine

Frequently Asked Questions

Does this fit the GMT360 Envoy XUV?
Yes, this is a direct fit for the 2004-2005 GMC Envoy XUV equipped with the LL8 engine.

Do these iridium spark plugs require gapping before installation?
These plugs arrive factory pre-gapped, though carefully checking the gap with a feeler gauge prior to torquing is standard practice.

The GMC Utility Caliber

Engineered for the rigorous duty demands of heavy-payload utility vehicles, this ignition kit maintains reliable secondary spark energy during stop-and-go driving, loaded hauling, and steep grade climbing.