Denso 3431 Spark Plug

Denso Iridium Long Life Spark Plug 3431

The Denso 3431 Iridium Long Life spark plug is built for OE-level ignition performance, durability, and emissions control. It uses an iridium center electrode with a platinum chip ground tip to support consistent spark delivery in demanding daily driving conditions.

Compatible With Mitsubishi Lancer, Endeavor, Galant, and Eclipse applications, this plug is a direct-fit secondary ignition service part for select 2004-2015 models. The Denso Iridium Long Life line focuses on extended service life and stable ignition performance for vehicles that call for a precise OE-style spark plug.

Key Features

• Part number 3431 from Denso Iridium Long Life
• Iridium center electrode tip material for durable spark performance
• Platinum chip ground electrode tip design
• 5000 ohm resistor for ignition noise suppression
• 0.8 pre-gap size for OE-style fitment
• 14.00 mm thread diameter, 19.00 mm reach, and 16.0 mm hex size
• Flat seat design with standard ground configuration
• Fits Mitsubishi Lancer, Endeavor, Galant, and Eclipse applications

Product Details

Denso 3431 is an ignition spark plug engineered to meet strict OE performance, durability, and emissions standards. Its copper core center electrode supports heat transfer, while the iridium tip helps maintain stable ignition characteristics over long service intervals. The nickel ground electrode core and platinum chip tip work together to support reliable combustion in select Mitsubishi engines. This part cross-references Denso Auto Parts K20PSR-B8 for the same application.

Common Issues This Part Can Address

• Engine misfire caused by worn spark plug electrodes
• Hard starting from degraded ignition performance
• Rough idle related to inconsistent spark delivery
• Reduced fuel economy from inefficient combustion
• Check engine light concerns tied to spark plug wear

Installation Notes and Tips

Verify thread diameter, reach, seat type, and pre-gap before installation. Use the vehicle service specification for final gap and torque settings, and inspect ignition coils and plug wires during service. This spark plug fits 2013-2015 Mitsubishi Lancer, 2008-2010 Mitsubishi Lancer, 2010-2011 Mitsubishi Endeavor, 2004-2008 Mitsubishi Endeavor, 2004-2007 Mitsubishi Galant, and 2005 Mitsubishi Eclipse.

Quality Assurance

Denso manufactures this spark plug to OE performance, durability, and emissions standards for select Mitsubishi applications. Part number 3431 is built for consistent ignition service in vehicles that require an iridium long-life plug.