High Performance Ignition Coil for GMC Envoy (2005-2009) 5.3L

High-Performance UF414 Ignition Coils for 2005-2009 GMC Envoy (LH6 / GMT360)

Designed to replace degrading factory coils, this 8-pack of high-output ignition coils restores proper voltage delivery to the spark plugs, eliminating misfires and stabilizing idle on the 5.3L V8.

The Stock Envoy GMT360 Ignition Weakness

The factory ignition coils on the LH6 5.3L engine are highly susceptible to thermal degradation due to their location directly above the exhaust manifolds. Over thousands of heat cycles, the internal epoxy potting breaks down, increasing internal electrical resistance. This thermal breakdown leads to a weak spark event, resulting in part-throttle hesitation, rough idling, and under-load misfires (often triggering P0300-series OBD-II codes). Furthermore, the stock coil winding ratios often struggle to provide adequate spark energy as the spark plug gap naturally increases with wear, causing incomplete combustion, diminished fuel economy, and poor throttle response.

The Engineering Solution

These upgraded UF414 replacement coils are engineered to exceed OEM specifications by utilizing high-grade copper windings with an optimized turns ratio, delivering a hotter, more consistent spark across the entire RPM range. The core is encased in a premium high-temperature epoxy resin that actively resists heat soak from the cylinder heads and exhaust manifolds, preventing internal shorting. The robust silicone boots and improved terminal contacts ensure maximum voltage transfer to the spark plug without arcing or dielectric breakdown. By guaranteeing complete combustion per cylinder cycle, this coil pack upgrade restores lost power, smooths out the Gen IV LS idle, and provides reliable ignition performance under heavy loads or towing conditions.

Technical Specifications

Compatibility

• 2005-2009 GMC Envoy Denali (5.3L V8)
• 2005-2006 GMC Envoy XL Denali (5.3L V8)
• 2005-2006 GMC Envoy XL SLT/SLE (5.3L V8)
• Fits all 2005-2009 V8 GMT360/GMT370 models requiring UF414 coils

The GMC Towing Caliber

For a GMT360 platform that frequently sees towing duty or heavy payloads, consistent spark delivery is critical to maintaining low-end torque and preventing detonation. This coil upgrade ensures your Envoy maintains peak pulling power and long-term reliability under prolonged engine loads.