NGK 6681 Spark Plug

NGK Iridium IX Spark Plug for High-Performance Ignition

The NGK Iridium IX Spark Plug, part number 6681, is built for precise ignition performance in demanding automotive applications. This DR8EIX plug combines an iridium center electrode with a nickel ground electrode and a 5,000-ohm resistor for stable spark delivery and reliable operation.

Compatible with select Ferrari and Lamborghini applications, including Ferrari Testarossa, Ferrari 348 models, Ferrari Mondial variants, and Lamborghini Diablo fitments listed below, this NGK Iridium IX Spark Plug 6681 is a direct replacement option for vehicles requiring the DR8EIX specification.

Key Features

• Iridium center electrode tip material for consistent spark performance
• Copper core center electrode for efficient heat transfer
• Nickel ground electrode with taper cut tip design
• 5,000-ohm resistance for ignition system stability
• Pre-gapped at .032 inches
• Flat seat, 12 mm thread diameter, .75 reach, and 18 mm hex size
• Manufacturer heat range 8 for specified engine applications

Product Details

NGK’s Iridium IX line is engineered for drivers who need dependable ignition performance and OE-level manufacturing consistency. The DR8EIX spark plug uses an iridium firing tip to support strong spark concentration, while the copper core helps manage heat under operating conditions. With a standard ground configuration and stud terminal type, this plug is built to match the specifications required by select Ferrari and Lamborghini engines. This part cross-references DENSO Auto Parts 5372 for the same application.

Common Issues This Spark Plug May Address

• Hard starting caused by worn or fouled spark plugs
• Rough idle from inconsistent ignition firing
• Misfire conditions related to degraded plug electrodes
• Reduced throttle response from weak spark delivery
• Maintenance replacement for DR8EIX-spec ignition service

Installation Notes and Tips

Verify the required gap and heat range before installation. This plug is listed with a .032-inch pre-gap, while fitment notes show application-specific gaps such as 0.024 inches for the Lamborghini Diablo and 0.025 inches for several Ferrari models. Confirm the vehicle’s service specification before use, and inspect the ignition system, threads, and sealing surface during replacement. Fits 1997-2000 Lamborghini Diablo, N/A. Fits 1993-1995 Ferrari 348 Spider, N/A. Fits 1993-1994 Ferrari 348 GTB, N/A. Fits 1993-1994 Ferrari 348 GTS, N/A. Fits 1989-1993 Ferrari Mondial t, N/A. Fits 1990-1992 Ferrari 348 TB, N/A. Fits 1989-1992 Ferrari 348 TS, N/A. Fits 1985-1991 Ferrari Testarossa, N/A. Fits 1986-1988 Ferrari Mondial 3.2, N/A. Fits 1980-1985 Ferrari Mondial 8, N/A.

Quality Assurance

NGK is a long-established OE spark plug manufacturer with broad coverage across domestic and import vehicles, motorcycles, marine engines, and small engines. The brand’s North American manufacturing and distribution network supports consistent product availability and OE-focused production standards for applications like the NGK 6681 spark plug.