Denso 3509 Spark Plug

Denso Iridium Long Life Spark Plug for Tacoma

The Denso 3509 Iridium Long Life (SIP) spark plug is built for Toyota Tacoma applications that call for OE-level ignition performance and emissions control. It uses an iridium center electrode, platinum needle ground tip, and a 0.8 mm pre-gap to support consistent spark delivery in 2016-2023 Tacoma models.

Designed for the Toyota Tacoma, this spark plug follows Denso’s Iridium Long Life product line for extended service intervals and stable combustion performance. The 3509 part number is also cross-referenced as DENSO Auto Parts FK20HR-A8 and Toyota 90919-01287 for the same application.

Key Features

• Iridium center electrode tip material for precise spark delivery
• Platinum needle ground electrode tip design with needle-to-needle configuration
• Copper center electrode core and nickel ground electrode core materials
• 0.8 mm pre-gap size for OE-style setup
• 5000 ohm resistance for ignition system compatibility
• Flat seat design, 14.00 mm thread diameter, 26.50 mm reach, and 16.0 mm hex size
• Manufacturer heat range 20

Detailed Description

Denso 3509 is an Iridium Long Life spark plug engineered to meet strict OE performance, durability, and emissions standards. The iridium center electrode helps maintain stable ignition characteristics, while the platinum needle ground tip and needle-to-needle ground configuration support efficient spark transfer under everyday driving conditions. For Tacoma owners looking for a direct-fit ignition service part, this plug matches the factory-style specifications used across 2016-2023 Toyota Tacoma applications.

Compatible With 2018-2023 Toyota Tacoma, N/A; Fits 2017 Toyota Tacoma, N/A; Fits 2016 Toyota Tacoma, N/A from 08/2015. The Denso 3509 is a practical choice when replacing worn spark plugs on a Toyota Tacoma and restoring OE-style ignition performance.

What It Helps Address

• Hard starting caused by worn spark plug electrodes
• Rough idle from inconsistent ignition firing
• Misfire conditions related to degraded spark plugs
• Reduced fuel economy from inefficient combustion
• Loss of throttle response from weak spark output

Installation Notes and Tips

Verify engine application and match the plug’s thread diameter, reach, seat type, and heat range before installation. Check the pre-gap against service specifications for the vehicle, and inspect ignition coils and boots during spark plug replacement to avoid repeat misfire concerns. Use proper torque procedures for the flat-seat design to help prevent thread or sealing damage.

Quality Assurance

Denso manufactures this spark plug to OE performance, durability, and emissions standards, with specifications aligned to factory-style Toyota Tacoma service requirements. The Denso 3509 is built for consistent ignition performance in the listed Tacoma model years.