For Lexus IS250 models covered by DENSO’s June 2026 application table with a 4GR-FSE engine, the listed normal-or-equivalent spark plug is DENSO FK20HBR11, with six plugs required. The genuine Lexus part number listed depends on the vehicle code: 90919-01249 for GSE20/GSE25 and 90919-01249-79 for GSE30/GSE35. Confirm your market, model year and vehicle code before ordering; a replacement can restore normal operation when plugs are worn, but the available sources do not establish a horsepower or fuel-economy gain beyond a healthy engine’s normal condition.
Which spark plugs fit a Lexus IS250?
DENSO’s application table, last updated June 2026, lists the following applications for IS250 vehicles with 4GR-FSE engines. These are catalog entries, not a VIN lookup or a market-specific Lexus maintenance schedule.
| DENSO vehicle code | Engine listed | DENSO normal-or-equivalent plug | Genuine part number listed | Quantity |
|---|---|---|---|---|
| GSE20/GSE25 | 4GR-FSE(D-4) | FK20HBR11 | 90919-01249 | 6 |
| GSE30 | 4GR-FSE | FK20HBR11 | 90919-01249-79 | 6 |
| GSE35 | 4GR-FSE | FK20HBR11 | 90919-01249-79 | 6 |
Use DENSO’s spark-plug application information alongside the vehicle’s manual to confirm the exact application. DENSO cautions that catalog information can change. Verify the vehicle code, market and model year, and check the listing quantity and part number before purchase.
Can new spark plugs boost performance and efficiency?
They can help recover normal operation if the existing plugs are worn, but that is different from upgrading a healthy engine. DENSO explains that electrode wear enlarges the spark gap; when the gap exceeds its limit, ignition stability can deteriorate. Its general guidance connects plug problems with possible poor starting, unstable idle, reduced horsepower, poorer fuel economy and adverse exhaust quality. These are general spark-plug effects, not measured results for the IS250.
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- This 6 pack NGK Laser Iridium Spark Plug is compatible with Lexus IS250 2015, 2014, 2013, 2012, 2011, 2010, 2009, 2008, 2007, 2006 2.5L V6
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No IS250-specific horsepower or fuel-economy gain figure is established by the cited official material. If the car already runs properly and its plugs are within the vehicle maker’s service requirements, the sources do not support expecting new plugs to improve performance or mileage beyond normal condition.
When should you replace the plugs?
Follow the maintenance schedule for your specific vehicle and market. DENSO’s generic replacement guidance gives approximately 100,000 km for its long-life Iridium Tough/Iridium Plus and platinum categories, and approximately 20,000 km for its Iridium Power, Ni-TT and conventional categories. These are manufacturer guidance figures for broad plug categories, not Lexus-prescribed IS250 intervals; DENSO also notes that driving conditions can shorten economic life. Confirm which plug family and interval apply in your vehicle’s manual.
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- This 6 pack NGK Ruthenium HX Spark Plug is compatible with Lexus IS250 2015, 2014, 2013, 2012, 2011, 2010, 2009, 2008, 2007, 2006 2.5L V6
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How to choose the right replacement
- Match the application by vehicle code, market and model year, using the owner’s manual and DENSO’s current application table.
- Check the dimensions and heat range specified for the vehicle. DENSO cautions against relying on cross-reference alone because specifications can differ by manufacturer.
- For a modified engine, do not assume the standard plug remains suitable. DENSO notes that tuning may require a different heat range; incorrect selection can damage the engine.
- Buy the correct part number and quantity. The cited catalog lists six plugs for each covered vehicle code.
DENSO’s official precautions state: “Select appropriate spark plugs with the correct dimensions and heat range by checking vehicle manual, maintenance manual and this catalogue’s or websites’ application table.” See its spark-plug precautions.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.Installation: use the vehicle-specific procedure
Correct installation torque matters. DENSO directs users to the vehicle manufacturer’s repair manual for the specific procedure. The exact IS250 torque specification, access steps and labor time are not established here, so do not substitute a generic torque value or assume an installation method from another engine. If you do not have the correct repair information or tools, have a qualified technician perform the work.
Quick Recap
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- 【OE Part Numbers】:Spark Plug compatible to 6858 DFH6B11A 1UXP18110 BY483DFH6B.Please confirm the compatibility according to the year/make/model of your vehicle and the OE number of the replaceable part
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- [Reference Number]: 6858, DFH6B11A, XP5325, AI5325, BY483DFH6B
- [Vehicle Fitment]: This automotive replacement spark plugs for Lexus IS250 V6 2.5L 2006-2015, IS350 3.5L 06 07 08 09 2010 2011 2012 2013 2014 2015 2016 2017, IS300 & RC300 3.5L 2016-2017, GS350 3.5L 2007-2015, GS450h 3.5L 2007-2011, GS300 3.0L 2006, RC350 3.5L 2015-2017
- [Exceptional Fuel Efficiency]: Our sparkplugs feature a 0.6mm finewire iridium centerwire tip design, coupled with advanced laser welded technology. This innovative combination ensures maximum fuel efficiency, allowing your engine to perform at its best while minimizing fuel consumption
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Rank #3
- Genuine DENSO Parts
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- TRUST IN DENSO: The automotive industry has recognized the DENSO commitment to quality through such prestigious awards as the Deming Award for Quality, the J;D; Power and Associates Chairman's Award, and numerous supplier awards for quality
- REDUCE EMISSIONS AND MISFIRES: The patented DENSO Spark Plug enables complete fuel ignition in the combustion chamber; It virtually eliminates erratic starts caused by poor fuel mixtures and excessive soot buildup; The DENSO Spark Plug employs a unique ground electrode designed to generate a larger spark nucleus at the point of ignition; Greater spark energy means improved flame travel, producing more complete, consistent, and efficient combustion
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