4pcs Upstream and Downstream O2 Sensor 1 Sensor 2 Bank 1 Bank 2 for 1998 1999 2000 Lexus GS400 V8-4.0L Direct Plug-In Replacement Oxygen O2 Sensor 2 Front + 2 Rear for 1998-2000 Lexus GS400 V8 4Pcs O2 Oxygen Sensor Upstream + Downstream For 98 99 00 Lexus GS400 V8-4.0L Warranty: 1 year umlimited miles. Please check the description or use the year/make/model drop down bar and interchangeable part numbers to confirm the compatibility before purchase.