Autolite AP5503 Spark Plug

Autolite Platinum Spark Plug AP5503

Autolite Platinum Spark Plug AP5503 is built for drivers who want OE-style ignition performance with platinum durability. It delivers easier starts, quicker acceleration, and improved fuel economy while maintaining the form, fit, and function expected for a wide range of foreign and domestic applications.

The Platinum Spark Plug line focuses on long service life and consistent ignition performance. With a platinum center electrode, nickel ground electrode, ceramic insulator, and resistor design, AP5503 is a practical replacement for vehicles that call for a 14 mm, flat-seat plug with a 0.044 in pre-gap.

Key Features

• Platinum center electrode tip and core material for improved durability versus standard copper plugs
• Nickel ground electrode with tapered tip design for stable spark delivery
• Pre-gapped at 0.044 in (1.10 mm)
• 14.0 mm thread diameter, 5/8 in hex size, and 0.750 in reach
• Resistor spark plug with 4000 ohm resistance
• Ceramic insulator with mid-projection design
• OE-style replacement for many Saab, Toyota, Honda, Acura, Nissan, Mazda, and related applications

Detailed Description

Autolite AP5503 is a platinum spark plug engineered for dependable ignition performance in vehicles that specify this plug style and gap. The platinum center electrode helps maintain consistent firing characteristics over time, while the nickel ground electrode and resistor construction support steady operation in everyday driving. This makes AP5503 a solid choice for owners servicing older import vehicles such as the Saab 900 and 9000, Toyota Celica, Toyota Supra, Honda Civic, Acura Integra, and Nissan Maxima.

Autolite positions the Platinum Spark Plug line as an OE-form, fit, and function replacement across many makes and models. AP5503 follows that approach with a flat seat, stud terminal, standard center electrode design, and mid-projection ceramic insulator. This part number, AP5503, is also a direct reference point for shoppers comparing ignition tune-up parts for import applications.

This part cross-references Anchor 3128 and Global Parts Distributors LLC 2097 for the same application.

What It Helps Address

• Hard starting caused by worn or fouled spark plugs
• Rough idle from inconsistent ignition firing
• Reduced throttle response during acceleration
• Fuel economy loss related to degraded spark performance
• Misfire symptoms tied to aged secondary ignition components

Installation Notes and Tips

Verify the vehicle’s required spark plug gap before installation, since fitment notes vary by application and some vehicles call for a different preset gap than the plug’s 0.044 in specification. Confirm thread diameter, reach, seat type, and terminal style against the original plug before service. For best results, install AP5503 on the specified maintenance interval and inspect ignition wires, coils, and related secondary ignition parts at the same time.

Compatible With 2005 Saab 9-2X, N/A; 1999-2005 Saab 9-3, N/A; 1998 Saab 900, N/A; 1994 Saab 900, N/A; 1995-1998 Saab 900, N/A; 1990-1998 Saab 9000, N/A; 1995-1997 Saab 900, N/A; 1995-1997 Saab 9000, N/A; 1986-1994 Saab 900, N/A; 1994 Saab 9000, N/A; 1987-1990 Saab 9000, N/A; 1988-1993 Toyota Celica, N/A; 1989-1992 Toyota Cressida, N/A; 1986-1992 Toyota Supra, N/A; 1986-1991 Acura Integra, N/A; 1988-1991 Honda Civic, N/A; 1988-1991 Honda CRX, N/A; 1985-1991 Nissan Maxima, N/A; 1986-1990 Acura Legend, N/A; 1988-1990 Honda Prelude, N/A; 1989-1990 Nissan Pulsar NX, N/A; 1989-1990 Nissan Sentra, N/A; 1988-1989 Mazda 323, N/A; 1984-1989 Nissan 300ZX, N/A; 1987-1989 Nissan D21, N/A; 1987-1989 Nissan Pathfinder, N/A; 1987-1989 Toyota Camry, N/A; 1986-1989 Toyota Celica, N/A; 1985-1989 Toyota MR2, N/A; 1987-1989 Toyota Supra, N/A; 1984-1988 Nissan 200SX, N/A; 1988 Toyota 4Runner, N/A; 1988 Toyota Corolla, N/A; 1985-1988 Toyota Corolla, N/A; 1985 Saab 900, N/A.

Quality Assurance

Autolite supplies ignition products to the automotive aftermarket and original equipment manufacturers, and the Platinum Spark Plug line is built around OE-style fitment and consistent manufacturing standards.