NGK 7559 Spark Plug

NGK Iridium IX Spark Plug 7559

NGK Iridium IX Spark Plug 7559 is built for drivers who want consistent ignition performance, stable combustion, and OE-level fitment across a wide range of domestic applications. This spark plug combines an iridium center electrode with a nickel ground electrode and a tapered seat for dependable service in compatible Ford, Buick, Chevrolet, Pontiac, Oldsmobile, Lincoln, Mercury, Jeep, and Cadillac engines.

The Iridium IX line focuses on precise ignition characteristics and durable electrode materials. Part number 7559 uses a 14 mm thread, 0.46 reach, 5/8 hex, 0.060 pre-gap, and a 5000 ohm resistor for controlled spark delivery in the correct applications.

Key Features

• Iridium center electrode tip for consistent spark performance
• Copper core center electrode for efficient heat transfer
• Nickel ground electrode with taper-cut tip design
• Standard ground configuration with one ground electrode
• 5000 ohm resistor for ignition system noise control
• Tapered seat, 14 mm thread diameter, 0.46 reach
• NGK part number 7559, stock number 7559

Product Details

NGK is a long-established OE spark plug supplier with broad coverage for domestic and import vehicles. The Iridium IX Spark Plug line is built for applications that call for a tapered-seat plug with a 0.060 gap specification, and this part is listed across many classic Ford, GM, Jeep, Lincoln, Mercury, and Cadillac platforms. It is a direct-fit ignition service part for vehicles such as the Ford Mustang, Ford Thunderbird, Chevrolet Camaro, Pontiac Firebird, Jeep CJ7, and Lincoln Town Car in the listed model years and engine configurations.

This part cross-references Autolite XP26 and AP Exhaust 7559 for the same application.

Common Issues This Spark Plug Can Address

• Hard starting caused by worn or fouled spark plugs
• Rough idle from weak or inconsistent ignition output
• Misfire conditions related to electrode wear
• Reduced throttle response from degraded spark quality
• Maintenance replacement for high-mileage ignition service

Installation Notes and Tips

Verify the vehicle’s required gap before installation and compare it with the application notes listed for your exact year, make, and model. Several fitments in this catalog call for 0.050, 0.054, or 0.060 inch gap settings depending on emissions package and build date, so confirm the correct specification before use. Check thread diameter, reach, seat type, and terminal style against the original plug to ensure proper fit.

Compatible With 1989-1996 Ford Bronco, 1989-1996 Ford E-150 Econoline, 1986-1996 Ford E-150 Econoline Club Wagon, 1989-1996 Ford F-150, 1989-1996 Ford F-250, 1987-1995 Ford Mustang, 1991-1993 Ford Thunderbird, 1991-1993 Mercury Cougar, 1987-1992 Lincoln Mark VII, and many additional listed Buick, Chevrolet, Pontiac, Oldsmobile, Jeep, Cadillac, Lincoln, and Mercury applications.

Quality Assurance

NGK manufactures spark plugs with extensive OE experience and global production and distribution support. Part 7559 is built to original-equipment standards for durability and operational performance in the applications shown in the fitment data.