Autolite 46 Spark Plug

Autolite 46 Copper Resistor Spark Plug

Autolite 46 is a copper resistor spark plug built for OE-style ignition performance in a wide range of classic Ford and Mercury applications. It supports quick starts, smooth acceleration, and consistent fuel delivery while matching original form, fit, and function for many older vehicles.

The Copper Resistor Spark Plug line focuses on dependable everyday ignition performance with a copper center electrode, nickel tip materials, and a ceramic insulator. For drivers restoring or maintaining Ford Mustang, Ford Bronco, and Mercury Capri models, Autolite 46 provides a straightforward OE replacement option.

Key Features

• Copper center electrode core for stable ignition performance
• Nickel center and ground electrode tip materials
• Resistor design with 4000 resistance
• Pre-gapped at 0.044 in. / 1.10 mm
• Tapered seat with 18 mm thread diameter
• 13/16 in. hex size for common service tools
• Mid-projection ceramic insulator design
• Stud-style electrical terminal

Detailed Description

Autolite 46 is an OE-style spark plug engineered for secondary ignition service where reliable spark delivery matters. Its copper core helps maintain consistent conductivity, while the nickel electrode materials and tapered ground electrode tip support steady combustion performance. The resistor design helps reduce electrical noise in ignition systems, and the mid-projection insulator configuration matches many factory-style applications.

This part number is a practical choice for owners searching for a replacement spark plug for 1960s through early 1980s Ford and Mercury vehicles. It is listed for applications such as Ford Mustang, Ford Bronco, Ford F-100, Ford F-250, Ford F-350, Mercury Capri, Mercury Cougar, and Mercury Monarch. Autolite 46 also cross-references DENSO Auto Parts 5005 for the same application.

What It Helps Address

• Hard starting caused by worn or inconsistent spark plugs
• Rough idle from degraded ignition performance
• Misfire symptoms related to plug wear or incorrect gap
• Reduced throttle response during acceleration
• Ignition noise concerns in resistor-equipped systems

Installation Notes

Verify the vehicle’s original plug specification before installation, including thread diameter, reach, seat type, and gap. This plug is pre-gapped at 0.044 in. / 1.10 mm, but final gap should always be checked against the vehicle’s service requirements. Confirm the correct application for your Ford Mustang, Ford Bronco, or Mercury Capri before installation.

Use the proper 13/16 in. spark plug socket and install to the manufacturer’s torque specification. Inspect ignition wires, coil condition, and plug wells during service to help maintain consistent performance.

Quality Assurance

Autolite supplies ignition products to the automotive aftermarket and OE channels, and this spark plug is built to OE form, fit, and function standards for a broad range of domestic and foreign applications.