Ignition Coil and Iridium Spark Plugs for Jaguar XK8 (2003-2006) 4.2L

Direct-Fit Ignition Coil and Iridium Spark Plug Service Kit for 2003-2006 Jaguar XK8

What it Does: Replaces degraded factory coil packs and worn plugs with matched, high-dielectric coil-on-plug assemblies and fine-wire iridium spark plugs to restore factory secondary ignition voltage, cure misfires, and stabilize idle quality.

The Stock XK8 Thermal Breakdown and Secondary Voltage Loss

The Jaguar AJ34 engine bay suffers from severe thermal cycling under the coil cover trays, leading to micro-cracking in factory epoxy insulation and internal copper winding degradation over time. This breakdown causes high-load secondary voltage leakage, intermittent P0300-P0308 misfires, rough idle, and unburned fuel entering the catalytic converters. Concurrently, standard electrode erosion widens the spark gap, overstressing aging coil packs and triggering hesitation under acceleration.

The Engineering Solution

This comprehensive tune-up kit features eight direct-replacement ignition coils engineered with high-grade copper windings and silicone dielectric boots that resist heat soak up to 400°F. Paired with eight fine-wire iridium spark plugs, the setup requires lower ignition voltage to arc, ensuring rapid flame propagation and reliable combustion under high cylinder pressures. Heavy-duty blade terminals guarantee clean signal delivery from the ECM with zero wiring modifications.

Technical Specifications

Compatibility

• 2003 Jaguar XK8 Base Coupe & Convertible 4.2L V8
• 2004 Jaguar XK8 Base Coupe & Convertible 4.2L V8
• 2005 Jaguar XK8 Base Coupe & Convertible 4.2L V8
• 2006 Jaguar XK8 Base Coupe & Convertible 4.2L V8
• 2006 Jaguar XK8 Victory Edition Coupe & Convertible 4.2L V8

The Jaguar Precision Ignition Standard

Engineered to meet stringent European OBD-II parameters, this ignition service kit prevents phantom fault codes and keeps your grand tourer operating with smooth, factory-correct power delivery and zero check-engine lights.