Bosch 9781 Spark Plug

Bosch OE Fine Wire Iridium Spark Plug 9781

Bosch 9781 is an OE Fine Wire Iridium spark plug built for consistent ignition performance and extended service life. It uses an ultra-fine iridium center electrode firing pin to support efficient spark delivery in Mitsubishi Mirage and Mirage G4 applications.

The Bosch OE Fine Wire Iridium line focuses on OE-style ignition performance with durable materials and precise electrode design. For drivers searching for a Bosch 9781 spark plug for 2014-2024 Mitsubishi Mirage or Mirage G4, this plug matches the factory-style 4-cycle ignition setup with a 14 mm thread diameter, flat seat, projected insulator, and resistor design.

Key Features

• OE Fine Wire Iridium product line from Bosch
• Iridium center electrode tip with fine wire design
• Nickel ground electrode with standard J-gap configuration
• Resistor spark plug with 6000 resistance
• 14 mm thread diameter, 26.5 mm reach, and 16 mm hex size
• Ceramic insulator with projected insulator type
• Flat seat and non-removable nut terminal
• Manufacturer heat range 7

Detailed Description

Bosch Part Number 9781 is engineered for OE-style ignition performance in secondary ignition systems. The iridium center electrode helps maintain a stable spark point, while the copper core and nickel ground electrode support reliable heat transfer and consistent operation. This spark plug is specified with a 1.1 pre-gap, standard ground tip design, and a single ground electrode for factory-style service replacement.

Compatible With 2014-2015 Mitsubishi Mirage, N/A; 2017-2020 Mitsubishi Mirage, N/A; and 2017-2024 Mitsubishi Mirage G4, N/A. If you are replacing worn plugs on a Mitsubishi Mirage or Mitsubishi Mirage G4, Bosch 9781 provides the OE Fine Wire Iridium configuration called out for these applications. Bosch 9781 is also a direct search match for shoppers comparing Bosch 9781 against OE-style iridium spark plug options for Mitsubishi Mirage and Mirage G4 maintenance.

Common Issues This Part Can Address

• Rough idle caused by worn spark plug electrodes
• Hard starting related to degraded ignition performance
• Misfire symptoms from inconsistent spark delivery
• Reduced fuel efficiency from aging plugs
• Loss of throttle response from plug wear

Installation Notes and Tips

Verify the engine uses a 14 mm, flat-seat, 4-cycle spark plug with the listed reach and heat range before installation. Check the gap against the vehicle specification prior to service, and inspect ignition coils and plug wells for contamination or wear while the plugs are removed. Use the vehicle service procedure for torque and replacement intervals.

Quality Assurance

Bosch manufactures this spark plug as part of its OE Fine Wire Iridium line, using iridium center electrode technology and OE-style construction for consistent ignition service. This part cross-references no listed aftermarket numbers for the same application.