Ignition Coil and Iridium Spark Plugs for Jaguar XJR (2004-2009) 4.2L

High-Output Ignition Coil and Iridium Spark Plug Kit for 2004-2009 Jaguar XJR

Direct-fit replacement ignition tune-up kit: Restores precise secondary ignition delivery and eliminates high-RPM misfires across all 8 cylinders in supercharged AJ-V8 platforms.

The Stock XJR Ignition Breakdown

The supercharged AJ34S engine operates under dense charge pressures and intense under-hood thermal cycles. Over time, OEM coil pack epoxy potting degrades, causing internal insulation breakdown, micro-arcing, and secondary voltage leakage. Worn spark plug electrodes further increase electrical resistance, overloading the primary coil circuit and inducing cylinder misfires (P0300–P0308 codes), erratic idle, and boost-cut hesitation.

The Engineering Solution

This ignition kit pairs eight direct-fit coil-on-plug assemblies with eight fine-wire iridium spark plugs. The coil assemblies feature high-grade internal copper windings and reinforced dielectric thermoplastic housings that withstand heat soak and prevent voltage bypass. The fine-wire iridium spark plugs reduce required firing voltage, provide superior anti-fouling capabilities, and stabilize flame kernel growth under boost.

Technical Specifications

Compatibility

• 2004 Jaguar XJR Base Sedan 4.2L V8 Supercharged
• 2005 Jaguar XJR Base Sedan 4.2L V8 Supercharged
• 2006 Jaguar XJR Base Sedan 4.2L V8 Supercharged
• 2007 Jaguar XJR Base Sedan 4.2L V8 Supercharged
• 2008 Jaguar XJR Base Sedan 4.2L V8 Supercharged
• 2009 Jaguar XJR Base Sedan 4.2L V8 Supercharged

The Jaguar Engineering Standard

Engineered to exact European mechanical tolerances, this direct replacement set integrates seamlessly with the factory engine management system, maintaining proper primary resistance values to guarantee zero check-engine lights and clean combustion.