NGK 6544 Spark Plug

Brand NGK 6544
Resistance 5000
Ground Electrode Tip Design Taper cut
Ground Configuration Standard
Ground Electrode Core Material Nickel
Electrical Terminal Type Non-removable nut
Center Electrode Core Material Copper
Center Electrode Tip Material Iridium
Pre-Gap Size .036
Ground Electrode Quantity 1
Hex Size 5/8
Insulator Height 50.00
Manufacturer Heat Range 9
Seat Type Flat
Reach .75
Thread Diameter 10.00
Part Number Imr9d-9h
Stock Number 6544
Fits —

Laser iridium design. Iridium tip and copper core for precise ignition performance.

OE supplier heritage. Built by NGK, a long-time original equipment spark plug manufacturer.

Standard spark plug. Flat seat and non-removable nut for a straightforward replacement.

Cross-references NGK 6544 and 31911-HW1-671 for the same application. See all 2.

$23.92Free shipping
In stock · usually ships same day before 1pm CST
Step 1 — Confirm fitment
Free return shipping if it doesn't fit when you check fitment here first.
Select your vehicle to confirm fitment
Verify this part fits before purchasing — free returns if it doesn't
Step 2 — Quantity
Order total $23.92
Free shipping to the continental U.S.
Free returns within 60 days if it doesn't fit when fitment is verified.

NGK Laser Iridium Spark Plug 6544

NGK 6544 is a Laser Iridium spark plug built for precise ignition performance in applications that call for a 10 mm, flat-seat plug with a .75 reach and .036 pre-gap. It uses an iridium center electrode tip, a nickel ground electrode, and a 5000-ohm resistor to support stable spark delivery and consistent engine operation.

Key Features

  • Laser Iridium design with an iridium center electrode tip for durable spark performance
  • 5000-ohm resistor helps control electrical noise in the ignition system
  • Flat seat, 10.00 mm thread diameter, and .75 reach for the specified application
  • .036 pre-gap for OE-style ignition setup
  • Nickel ground electrode with taper-cut tip design
  • Non-removable nut terminal for secure connection
  • Cross-reference part number: IMR9D-9H

Product Details

This NGK Laser Iridium Spark Plug is part number 6544 and is identified by stock number 6544. NGK’s Laser Iridium line focuses on OE-level construction and consistent ignition characteristics, making it a practical choice for drivers who need a direct-replacement spark plug with the correct heat range, terminal style, and electrode configuration. It is a fitment-specific ignition component for vehicles such as Honda Civic and Honda models that call for this exact plug specification.

Compatible With Honda Civic and other Honda applications that specify NGK 6544 / IMR9D-9H, this spark plug supports reliable combustion, clean starting, and steady idle quality when the engine is tuned for the listed dimensions and heat range. The copper core center electrode and iridium tip work together to promote efficient spark transfer under normal operating conditions.

What It Helps Address

  • Rough idle caused by worn or incorrect spark plugs
  • Hard starting from weak or inconsistent ignition output
  • Misfire conditions related to plug wear or improper gap
  • Reduced throttle response from degraded spark quality
  • Ignition noise concerns in systems that require a resistor plug

Installation Notes

Verify the engine calls for a 10 mm, flat-seat spark plug with a .75 reach, .036 pre-gap, and 5/8 hex before installation. Check the service manual for the correct torque specification and confirm the ignition system is in good condition before installing NGK 6544. For Honda Civic and related Honda applications, match the plug number and heat range exactly to the OE requirement.

Quality Assurance

NGK is a major OE spark plug supplier in North America with decades of automotive manufacturing experience. The brand’s OE-focused production and broad vehicle coverage support consistent part quality for applications that specify NGK 6544.

This part fits 0 vehicles
Always verify fitment with your vehicle's VIN if unsure. Submodel & trim restrictions may apply.
YearMakeModelPositionNotes
Directly replaces or cross-references 2 part numbers
Cross-reference numbers are provided for identification purposes only. Always confirm fitment before ordering.
NGK — 654431911-HW1-671