Denso 3473 Spark Plug

Denso Iridium Long Life Spark Plug 3473

Denso 3473 is an Iridium Long Life (SIP) spark plug built for OE-level performance, durability, and emissions control. It is a direct replacement choice for select Lexus applications, including Lexus IS350, GS350, LS460, and RC350 models.

The Iridium Long Life line focuses on stable ignition performance over extended service intervals. This plug uses an iridium center electrode, platinum needle ground tip design, and a needle-to-needle ground configuration to support consistent spark delivery in modern high-compression engines.

Key Features

• Part number 3473 from Denso’s Iridium Long Life (SIP) line
• Iridium center electrode tip material for precise ignition performance
• Platinum needle ground electrode tip design
• Needle-to-needle ground configuration
• Nickel ground electrode core material and copper center electrode core material
• 5000 ohm resistance
• 1.1 pre-gap size, 14.00 mm thread diameter, 26.50 mm reach
• Flat seat design with 16.0 mm hex size
• Manufacturer heat range 20

Product Details

Denso 3473 is engineered to meet strict OE performance, durability, and emissions standards. The iridium firing tip supports reliable ignition under demanding operating conditions, while the platinum needle ground design helps maintain consistent spark characteristics. This makes it a practical OE-style spark plug for drivers servicing Lexus IS250, IS350, GS350, LS460, LS600h, GS460, GS300, GS450h, IS F, and RC350 applications. This part cross-references DENSO Auto Parts FK20HBR11 and Toyota 90919-01249 for the same application.

Common Issues This Spark Plug Can Address

• Hard starting caused by worn spark plug electrodes
• Rough idle from inconsistent ignition output
• Misfire conditions related to aged plugs
• Reduced fuel economy from weak spark performance
• Loss of throttle response in high-mileage ignition systems

Installation Notes and Tips

Verify the vehicle’s engine code and existing plug specification before installation. Confirm the 1.1 mm pre-gap and use the correct torque procedure for the cylinder head material. Inspect ignition coils, boots, and plug wells during service to avoid repeat misfire concerns. Compatible With 2006-2016 Lexus IS250, 2006-2016 Lexus IS350, 2007-2016 Lexus LS460, 2008-2016 Lexus LS600h, 2013-2015 Lexus GS350, 2007-2011 Lexus GS350, 2006-2015 Lexus IS250, 2008-2014 Lexus IS F, 2007-2011 Lexus GS450h, 2011 Lexus GS460, 2008-2009 Lexus GS460, 2006 Lexus GS300, 2016-2017 Lexus RC300, 2015-2017 Lexus RC350, 2016 Lexus IS300, 2017 Lexus IS300, 2017 Lexus IS350, and 2017 Lexus LS460.

Quality Assurance

Denso manufactures this spark plug to OE performance, durability, and emissions standards, making it a dependable service part for Lexus ignition maintenance.