Ignition Coil and Iridium Spark Plugs for Cadillac STS (2006-2009) 4.4L

Direct-Fit Ignition Coil and Iridium Spark Plug Kit for 2006-2009 Cadillac STS

Primary Function: Restores factory secondary ignition voltage and prevents high-load spark blowout across the entire supercharged rev range.

The Stock STS LC3 Ignition Breakdown

Under forced induction, the supercharged 4.4L LC3 Northstar generates elevated cylinder pressures and severe underhood thermal soak. Over time, OEM coil-on-plug assemblies suffer dielectric breakdown and micro-fractures in the potting resin, leading to secondary voltage arcing to the cylinder head. Combined with worn factory spark plug gaps, this degradation causes spark quench under boost, rough idle, poor cold starting, and persistent P0300-series misfire codes.

The Engineering Solution

This 8-cylinder ignition overhaul kit pairs eight reinforced coil-on-plug units with fine-wire iridium spark plugs. Each coil is wound with high-purity electrolytic copper and sealed with high-dielectric epoxy to withstand intense thermal cycling. The matching iridium spark plugs feature a laser-welded fine-wire center electrode for reduced ignition voltage demand, superior flame kernel expansion, and long-term gap stability under elevated boost levels.

Technical Specifications

Compatibility

• 2006 Cadillac STS-V 4.4L Supercharged V8
• 2007 Cadillac STS-V 4.4L Supercharged V8
• 2008 Cadillac STS-V 4.4L Supercharged V8
• 2009 Cadillac STS-V 4.4L Supercharged V8
• Direct Interchange: UF564, UF-564, 12594176, 89017778, ITR4A15, 0997000940, D596A, 5C1613, E1064, 52-1854, IC644, 12597745, 12670154, 5599

The Cadillac Performance Standard

Engineered to meet the exact load and thermal tolerances of high-output luxury muscle platforms, this direct-replacement kit ensures precise spark timing, smooth combustion transitions, and instant throttle response under hard acceleration.