Autolite APP3924 Spark Plug

Autolite APP3924 Double Platinum Spark Plug

Autolite APP3924 is a Double Platinum spark plug built for OE-style replacement in a wide range of import and domestic engines. It uses platinum-to-platinum firing for longer service life, easier starts, quicker acceleration, and improved fuel efficiency.

With a 14 mm thread diameter, 0.750 in. reach, flat seat, 5/8 in. hex, and a 0.044 in. pre-gap, this Autolite spark plug is a direct-fit choice for many Audi, BMW, Toyota, Mitsubishi, Mercedes-Benz, and Volkswagen applications.

Key Features

• Double platinum firing design for extended plug life
• OE form, fit, and function for many foreign and domestic vehicles
• Platinum center and ground electrode tip materials
• Resistor type plug with 4000 resistance
• Ceramic insulator with mid-projection design
• Pre-gapped at 0.044 in. / 1.10 mm
• Flat seat, 14 mm thread, 0.750 in. reach, 5/8 in. hex

Product Details

The Autolite Double Platinum Spark Plug line is engineered for drivers who want an OE-style ignition part with durable platinum construction. APP3924 uses platinum on both the center and ground firing surfaces to promote consistent spark delivery and longer-lasting performance. This part cross-references Champion Spark Plug 71 for the same application.

Use Autolite APP3924 when replacing worn spark plugs in vehicles such as the Audi Q7, Toyota Prius, and Mitsubishi Outlander Sport, where OE-style fitment and the correct gap are important for smooth operation. The design supports reliable ignition performance across a broad range of applications listed in the fitment data.

What It Helps Address

• Hard starting caused by worn spark plugs
• Rough idle and inconsistent combustion
• Slow throttle response and reduced acceleration
• Fuel economy loss from weak ignition performance
• Misfire concerns related to plug wear or gap drift

Installation Notes

• Verify vehicle-specific fitment before installation.
• Confirm the required gap for your application; some vehicles in the fitment list call for a different gap than the plug’s pre-gap.
• Inspect coil boots, wires, and ignition components during service.
• Follow the manufacturer’s torque and service procedures for your engine.

Quality Assurance

Autolite supplies ignition products to the automotive aftermarket and original equipment manufacturers, and APP3924 is built to OE-style standards for form, fit, and function.