Autolite APP105 Spark Plug

Autolite APP105 Double Platinum Spark Plug

The Autolite APP105 is a Double Platinum spark plug built for OE-style fit, form, and function across a wide range of Ford, Mercury, Mazda, and Chevrolet applications. Its platinum-to-platinum firing design supports consistent spark performance, easier starts, quicker acceleration, and improved fuel efficiency.

For drivers searching for an OE replacement spark plug for a Ford Ranger, Ford Windstar, or Mazda B4000, the APP105 offers a practical upgrade path with the dimensions and terminal style needed for many factory ignition systems.

Key Features

• Double platinum firing design for longer service life and stable spark performance
• Platinum center electrode tip and platinum ground electrode tip
• Pre-gapped to 0.050 in. / 1.30 mm
• 14 mm thread diameter with 0.679 in. reach
• 5/8 in. hex size and stud terminal type
• Resistor spark plug with 4,000 ohm resistance
• Ceramic insulator with mid-projection design
• OE-style replacement for many domestic applications

Product Details

Autolite’s Double Platinum Spark Plug line is positioned as an OE-style replacement solution for drivers who want factory-matched fitment and dependable ignition performance. The APP105 uses platinum on both the center and ground electrodes to support more even wear over time, while the tapered seat and standard regular center electrode design help it align with many original equipment specifications. This part cross-references AMS Automotive 4417 for the same application.

Compatible With select 1977-2002 Ford, Mercury, Mazda, and Chevrolet vehicles, including applications such as 1990-1995 Ford Ranger, 1996-2002 Ford Windstar, 1991-1996 Ford Explorer, 1994-1996 Mazda B4000, and 1999 Chevrolet Silverado 1500. The APP105 part number is also commonly searched as Autolite APP105 spark plug for OE replacement ignition service.

Common Issues This Part Can Address

• Hard starting caused by worn spark plug electrodes
• Rough idle from inconsistent ignition firing
• Reduced throttle response during acceleration
• Fuel economy loss related to degraded spark performance
• Maintenance replacement for aging OE-style spark plugs

Installation Notes and Tips

• Verify vehicle-specific fitment by year, make, model, and engine application before installation.
• Check the pre-gap specification against the vehicle service information before use.
• Inspect ignition wires, coils, and boots during spark plug service to avoid repeat misfire concerns.
• Use the correct torque procedure for the tapered seat design to help prevent thread or sealing damage.

Quality Assurance

Autolite supplies ignition products to the automotive aftermarket and original equipment manufacturers, and the APP105 is built to OE-style specifications for broad domestic and import coverage. The Double Platinum construction is engineered for consistent ignition performance and long-term service in supported applications.