NGK 91356 Spark Plug

NGK Ruthenium HX Spark Plug 91356

NGK 91356 is a Ruthenium HX High Ignitability spark plug built for precise ignition performance and OE-style durability. It uses a ruthenium center electrode tip, a dual fine electrode ground design, and a 0.044 in pre-gap to support consistent spark delivery in the applications listed below.

Compatible With 2014-2020 Mitsubishi Outlander, 2011 Hyundai Elantra, 2010-2011 Kia Borrego, and 2009 Hyundai Genesis and Kia Borrego applications that call for this plug specification.

Key Features

• Ruthenium center electrode tip material for stable ignition performance
• Dual Fine Electrode - High Ignitability ground tip design
• 0.044 in pre-gap for listed vehicle applications
• 5000 ohm resistance
• Copper center electrode core and nickel ground electrode core
• Flat seat design with 12 mm thread diameter and 5/8 hex size
• NGK part number 91356 / LKR6AHX

Ruthenium HX Product Line

NGK’s Ruthenium HX High Ignitability line is focused on ignition consistency and long-term service performance. The plug design combines a ruthenium firing tip with a fine-electrode layout to support reliable spark formation in modern engines that require exact plug specifications.

Detailed Description

NGK 91356 is a secondary ignition spark plug engineered for specific Mitsubishi, Hyundai, and Kia applications. The plug’s 26.5 mm reach, heat range 6, and flat seat configuration are important for proper cylinder head fitment and combustion chamber performance. For vehicles such as the Mitsubishi Outlander, Hyundai Elantra, Kia Borrego, and Hyundai Genesis, using the correct plug specification helps maintain factory-style ignition behavior. This part cross-references Dorman - HELP 91356 for the same application.

Common Issues This Part Can Address

• Hard starting caused by worn spark plug electrodes
• Rough idle from inconsistent ignition output
• Misfire conditions related to plug wear or incorrect gap
• Reduced throttle response from degraded spark delivery
• Maintenance replacement for scheduled spark plug service

Installation Notes and Tips

• Verify engine application and match the listed fitment before installation.
• Set the spark plug gap to 0.044 in where required by the vehicle notes.
• Confirm the 12 mm thread diameter, 26.5 mm reach, and flat seat match the cylinder head specification.
• Use proper spark plug handling and torque procedures to avoid thread or insulator damage.
• Check ignition coils, boots, and related secondary ignition components during service.

Quality Assurance

NGK is a long-established OE supplier and manufacturer with broad coverage across domestic and import vehicles in North America. The brand’s manufacturing and distribution network supports consistent product standards for automotive ignition service.