Ignition Coil & Iridium Spark Plugs & Wire GMC Sierra 2500 HD 3500 HD (2020) 6.6L V8

High-Energy Ignition Coil & Iridium Plug Kit for GMC Sierra 2500/3500 HD

Replaces degraded OEM ignition components to restore optimal spark energy, eliminate RFI interference, and cure misfires on the 6.6L L8T V8 engine.

The Stock Sierra HD Ignition Breakdown

Under heavy thermal loads from constant towing or prolonged idling, the factory ignition coils and spark plug wires on the T1XX Sierra HD inevitably break down. The stock coil's internal epoxy degrades over time, altering primary and secondary resistance values. This causes voltage leaks and weakened spark delivery. Inadequate spark results in poor combustion efficiency within the L8T cylinders, directly manifesting as sluggish throttle response, random misfires, check engine lights (CEL), and engine hesitation, and noticeable drops in fuel economy.

The Engineering Solution

This comprehensive ignition overhaul kit is engineered to provide a 20% increase in spark energy over the OE factory components. The upgraded UF742 coils utilize premium high-conductivity copper windings encased in advanced, heat-resistant epoxy to prevent premature thermal breakdown. Capable of stepping up a standard 12V input to over 25,000V (maximum 26,000V with a precise 61:1 turns ratio), they deliver a robust and highly consistent spark. The included 41-114 iridium spark plugs feature an ultra-fine center electrode for superior ignitability, exceptional conductivity, and a high melting point to maximize complete combustion. Coupled with 8mm high-temperature silicone spark plug wires, protective heat shields, and wire separators, this system is designed to ensure maximum voltage transfer to the chamber while completely eliminating RFI electronic interference.

Technical Specifications

Compatibility

• 2020 GMC Sierra 2500 HD 6.6L V8 Gas
• 2020 GMC Sierra 3500 HD 6.6L V8 Gas

The Heavy-Duty Caliber

Built for the rigorous demands of heavy towing and high-payload hauling, this ignition kit ensures reliable, misfire-free power delivery when pulling heavy loads up steep grades, preventing drivability complaints and pre-ignition.

Common Questions

Will this ignition kit fit my 2020 GMC Sierra 2500 HD or 3500 HD with the 6.6L gas engine?
Yes, this kit is a direct fit for the 2020 GMC Sierra 2500 HD and 3500 HD equipped with the 6.6L L8T V8 gas engine.

Can I use this kit on the 6.6L Duramax diesel engine?
This ignition coil, spark plug, and wire kit is engineered specifically for the 6.6L L8T V8 gasoline engine.

What is included in the box?
The kit includes upgraded UF742 ignition coils, 41-114 iridium spark plugs, 8mm 748UU high-temperature silicone spark plug wires, protective heat shields, and wire separators.

How do the UF742 coils compare to the factory ignition coils?
They are built with high-conductivity copper windings and heat-resistant epoxy, delivering a 20% increase in spark energy over OE components and stepping 12V input up to 26,000V.

What part numbers does this kit match?
This kit matches part numbers UF742 (UF-742) for the ignition coils, 41-114 for the iridium spark plugs, and 748UU for the spark plug wire set.