Ignition Coil and Iridium Spark Plugs for Jeep Grand Cherokee (1999-2008) 4.7L

Direct-Fit High-Output Ignition Kit for 1999-2008 Jeep Grand Cherokee

What it Does: Complete 8-cylinder ignition overhaul kit engineered to replace degraded OEM coil-on-plug packs and worn spark plugs to restore factory combustion efficiency and eliminate misfires.

The Stock Grand Cherokee Coil Degradation and Spark Erosion

The 4.7L PowerTech V8 platform generates significant underhood thermal load that gradually breaks down OEM coil epoxy potting and internal copper windings. Over time, heat cycles cause dielectric failure, internal arcing, and micro-cracking in the secondary boot isolators. Combined with standard copper plug electrode erosion that widens plug gaps and spikes required secondary voltage, the stock ignition system suffers from random misfires (P0300-P0308 codes), rough idle, hesitation under towing load, and unburned hydrocarbon blow-by.

The Engineering Solution

This comprehensive kit features eight high-dielectric coil packs wound with high-conductivity oxygen-free copper and insulated with heavy-duty thermal-resistant epoxy potting. Paired with eight fine-wire iridium spark plugs, the assembly lowers the required ignition voltage while delivering a hotter, more stable spark kernel under high-load cylinder pressures. Direct-fit blade terminals and factory-keyed connectors ensure plug-and-play installation without harness modification.

Technical Specifications

Compatibility

• 1999-2004 Jeep Grand Cherokee (WJ Chassis) 4.7L PowerTech V8
• 2005-2008 Jeep Grand Cherokee (WK Chassis) 4.7L PowerTech V8

The Jeep Trail-Tested Durability Standard

Built to withstand continuous off-road vibration, heavy-duty towing, and high-temp trail crawls, this ignition kit restores the torque and throttle response required for demanding utility and 4x4 use.