Overview

Autolite 5143 is a copper resistor spark plug built for OE-style fit, form, and function. It is listed for a wide range of Ford, Mazda, Mercury, and Land Rover applications, including Ford Ranger, Ford Explorer, and Ford Mustang fitments.

With a copper center electrode, nickel ground electrode components, and a tapered seat design, this spark plug is specified for consistent ignition performance and the correct gap requirements shown in the fitment data.

Key Features

• Copper center electrode core for reliable ignition response.
• Nickel ground electrode tip and core materials.
• Resistor design for reduced electrical interference.
• Extra-long ceramic insulator for stable plug construction.
• OE-style fit, form, and function for listed applications.
• Part number 5143 for easy identification.

Detailed Description

Autolite 5143 is a copper resistor spark plug engineered around OE-style specifications, including a 14.0 mm thread diameter, 0.809 inch reach, tapered seat, and 0.054 inch pre-gap. The standard center electrode design and tapered ground electrode tip support dependable spark delivery in the applications shown. This part number 5143 is listed across multiple Ford platforms, along with Mazda B4000, Mercury Mountaineer, and Land Rover LR3 fitments.

Autolite positions this spark plug as an OE-form replacement for domestic and foreign vehicles, and the brands ignition product focus is reflected in the construction and application coverage. If you are servicing a Ford Explorer, Ford Ranger, or Ford Mustang, verify the exact year and gap specification against the fitment table before installation.

What It Helps Address

• Hard starting caused by worn spark plugs.
• Rough idle from inconsistent ignition output.
• Reduced throttle response during acceleration.
• Fuel economy loss related to degraded spark performance.
• Misfire concerns tied to incorrect plug wear or gap.

Installation Notes

Confirm the listed year, engine application, and spark plug gap before installation. The fitment data includes OE-style gap requirements that vary by vehicle, including 0.054 inch and 0.044 inch applications. Use the specified gap and torque procedure for the engine being serviced. Fits 2004-2005 Ford Ranger, 2005 Ford Mustang, and 2006-2010 Ford Explorer applications shown in the fitment data.

Quality Assurance

Autolite is a long-standing supplier of spark plugs to the automotive aftermarket and original equipment manufacturers. Part number 5143 cross-references Autolite 403 and Carlson 7060 for the same application.