NGK 91970 Spark Plug

NGK Laser Iridium Spark Plug 91970

NGK 91970 is a Laser Iridium spark plug built for OE-style ignition performance in a wide range of GM applications. It is specified for vehicles such as the Chevrolet Equinox, Malibu, and Trailblazer, along with Buick Encore GX and GMC Terrain models that call for a tapered-seat plug with a 0.028 in. gap.

Key Features

• Laser Iridium center electrode tip for stable spark delivery and long service life
• Standard ground electrode design with a single ground electrode
• Pre-gapped at 0.028 in. for listed OE-equivalent applications
• Tapered seat design with 12 mm thread diameter and 14 mm hex size
• 5000 ohm resistance for ignition system compatibility
• Copper core construction in both center and ground electrodes
• Heat range 8 for the specified factory service interval applications

Product Details

This NGK Laser Iridium Spark Plug is engineered to match original equipment requirements for select Buick, Chevrolet, and GMC vehicles. The iridium center electrode tip supports consistent ignition performance, while the standard ground configuration and tapered seat help maintain the OE-style fit called for in factory service applications. Part number 91970 is also identified as ILNAR8B7G and cross-references GM OE numbers 12683541 and 55490097 for the same application.

NGK has a long OE supply history and manufactures spark plugs for domestic and import vehicles across automotive, motorcycle, marine, and small engine categories. That OE background is reflected in the design focus of this plug, which is intended for factory-recommended service intervals and direct replacement use on listed vehicles.

Common Issues This Part Addresses

• Rough idle caused by worn spark plug electrodes
• Hard starting from weakened ignition output
• Misfire conditions tied to plug wear or incorrect gap
• Reduced throttle response from inconsistent spark delivery
• Maintenance replacement at the factory service interval

Installation Notes and Tips

• Verify vehicle application by year, make, and model before installation.
• Confirm the plug gap matches the listed 0.028 in. specification for your application.
• Use the correct torque procedure for tapered-seat spark plugs to avoid thread or sealing damage.
• Inspect ignition coils and boots during service to address related wear at the same time.
• Check the vehicle service manual for the exact replacement interval and tightening specification.

Quality Assurance

NGK is a major OE spark plug supplier with manufacturing and distribution operations in North America and globally. Part number 91970 is built to OE-equivalent standards for the listed applications, including 2021-2025 Buick Encore GX, 2021-2025 Chevrolet Equinox, 2021-2025 Chevrolet Malibu, 2022-2025 Chevrolet Trailblazer, 2021-2025 GMC Terrain, and other confirmed fitments.