{"product_id":"o2-oxygen-sensor-upstream-downstream-for-toyota-4runner-1996-2000-3-4l","title":"O2 Oxygen Sensor Upstream Downstream for Toyota 4Runner (1996-2000) 3.4L","description":"\u003ch2 style=\"font-size: clamp(18px, 3vw, 21px); margin-bottom: 15px; line-height: 1.3;\"\u003eDirect-Fit Upstream \u0026amp; Downstream Oxygen Sensor Kit for 1996-2000 Toyota 4Runner (N180)\u003c\/h2\u003e\u003cp\u003e\u003cstrong\u003eWhat it Does:\u003c\/strong\u003e This matched upstream and downstream oxygen sensor kit monitors exhaust air-fuel ratios and catalytic converter efficiency on the 1996-2000 Toyota 4Runner (\u003cstrong\u003eN180\u003c\/strong\u003e) powered by the \u003cstrong\u003e5VZ-FE 3.4L V6\u003c\/strong\u003e engine to maintain closed-loop fuel trim precision.\u003c\/p\u003e\u003ch3\u003eThe Stock Toyota 4Runner Sensor Failure\u003c\/h3\u003e\u003cp\u003eFactory oxygen sensors on the \u003cstrong\u003eN180\u003c\/strong\u003e chassis equipped with the \u003cstrong\u003e5VZ-FE 3.4L V6\u003c\/strong\u003e endure relentless thermal cycling, moisture intrusion, and carbon fouling over high mileage. Over time, the internal zirconia sensing element degrades and the integrated heater circuit fractures, delaying closed-loop ECU operation during cold starts. Sluggish voltage switching forces the ECM into rich fuel trims, triggering \u003cstrong\u003eP0135\u003c\/strong\u003e, \u003cstrong\u003eP0141\u003c\/strong\u003e, or \u003cstrong\u003eP0171\u003c\/strong\u003e fault codes while risking catalytic converter overheating.\u003c\/p\u003e\u003ch4\u003eCommon Symptoms of a Failing OEM Oxygen Sensor\u003c\/h4\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eCheck Engine Light \/ DTCs:\u003c\/strong\u003e Illuminated MIL with \u003cstrong\u003eP0135\u003c\/strong\u003e (upstream heater circuit), \u003cstrong\u003eP0141\u003c\/strong\u003e (downstream heater circuit), or \u003cstrong\u003eP0420\u003c\/strong\u003e catalyst efficiency faults.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eRough Idle \u0026amp; Hesitation:\u003c\/strong\u003e Delayed voltage feedback disrupts fuel trims, causing surging or sluggish throttle response under load.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePoor Fuel Economy:\u003c\/strong\u003e Rich open-loop operation drops MPG significantly, fouls spark plugs, and causes failed emissions testing.\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eThe Direct-Fit Zirconia Oxygen Sensor Solution\u003c\/h3\u003e\u003cp\u003eThis matched upstream and downstream sensor pair replaces worn factory units with OEM-grade zirconia ceramic sensing elements engineered for rapid light-off and accurate millivolt response. Laser-welded stainless steel housings shield the internal electrodes against exhaust condensation and thermal shock under heavy load. Pre-terminated factory-style connectors and OEM-spec wiring harnesses match the \u003cstrong\u003eE83185400CP\u003c\/strong\u003e specification for plug-and-play installation without splicing. Replacing both positions simultaneously restores balanced closed-loop feedback for the \u003cstrong\u003e5VZ-FE 3.4L V6\u003c\/strong\u003e.\u003c\/p\u003e\u003ch3\u003eWhat's Included\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e1 Upstream Oxygen Sensor (Direct-Fit)\u003c\/li\u003e\n\u003cli\u003e1 Downstream Oxygen Sensor (Direct-Fit)\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eTechnical Specifications\u003c\/h3\u003e\u003cdiv style=\"overflow-x: auto; margin-bottom: 20px;\"\u003e\u003ctable width=\"100%\" style=\"border-collapse: collapse; border: 1px solid #e0e0e0; font-size: 14px; min-width: 300px;\"\u003e\n\u003ctr style=\"background-color: #f9f9f9;\"\u003e\n\u003cth style=\"padding:10px; text-align: left; border: 1px solid #e0e0e0;\"\u003eFitment\u003c\/th\u003e\n\u003ctd style=\"padding:10px; border: 1px solid #e0e0e0;\"\u003e1996-2000 Toyota 4Runner\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth style=\"padding:10px; text-align: left; border: 1px solid #e0e0e0;\"\u003eEngine \/ Chassis\u003c\/th\u003e\n\u003ctd style=\"padding:10px; border: 1px solid #e0e0e0;\"\u003e5VZ-FE 3.4L V6 \/ N180\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background-color: #f9f9f9;\"\u003e\n\u003cth style=\"padding:10px; text-align: left; border: 1px solid #e0e0e0;\"\u003eStock Engine Output\u003c\/th\u003e\n\u003ctd style=\"padding:10px; border: 1px solid #e0e0e0;\"\u003e183 hp \/ 217 lb-ft\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth style=\"padding:10px; text-align: left; border: 1px solid #e0e0e0;\"\u003eInstallation Type\u003c\/th\u003e\n\u003ctd style=\"padding:10px; border: 1px solid #e0e0e0;\"\u003eDirect Bolt-On OEM Replacement (No Cutting or Welding)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background-color: #f9f9f9;\"\u003e\n\u003cth style=\"padding:10px; text-align: left; border: 1px solid #e0e0e0;\"\u003eReplaces OEM Part #\u003c\/th\u003e\n\u003ctd style=\"padding:10px; border: 1px solid #e0e0e0;\"\u003eE83185400CP\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/table\u003e\u003c\/div\u003e\u003ch3\u003eCompatibility\u003c\/h3\u003e\u003cul\u003e\u003cli\u003e1996-2000 Toyota 4Runner 3.4L (Upstream \u0026amp; Downstream Positions)\u003c\/li\u003e\u003c\/ul\u003e\u003ch3\u003eFrequently Asked Questions \u0026amp; Fitment Warnings\u003c\/h3\u003e\u003ch4\u003eDoes this fit the N180 4Runner?\u003c\/h4\u003e\u003cp\u003e\u003cstrong\u003eYes.\u003c\/strong\u003e This is a direct fit for the 1996-2000 Toyota 4Runner equipped with the \u003cstrong\u003e5VZ-FE 3.4L V6\u003c\/strong\u003e engine. \u003cstrong\u003eExcludes 2.7L 3RZ-FE 4-cylinder models; confirm your engine displacement and emissions specification before ordering.\u003c\/strong\u003e\u003c\/p\u003e\u003ch4\u003eWill replacing both sensors clear P0135, P0141, or P0420 codes?\u003c\/h4\u003e\u003cp\u003e\u003cstrong\u003eYes, for sensor-related faults.\u003c\/strong\u003e Replacing failed sensors eliminates heater circuit codes like \u003cstrong\u003eP0135\u003c\/strong\u003e and \u003cstrong\u003eP0141\u003c\/strong\u003e, though a persistent \u003cstrong\u003eP0420\u003c\/strong\u003e code after installation indicates a degraded catalytic converter.\u003c\/p\u003e\u003ch4\u003eIs any wiring modification required for installation?\u003c\/h4\u003e\u003cp\u003e\u003cstrong\u003eNo.\u003c\/strong\u003e Both units include OEM-style connectors matching \u003cstrong\u003eE83185400CP\u003c\/strong\u003e for plug-and-play installation; torque cleanly to factory specification without contaminating the sensor tip.\u003c\/p\u003e\u003ch3\u003eThe Toyota Heavy-Duty Standard\u003c\/h3\u003e\u003cp\u003eEngineered for high exhaust gas temperatures under towing loads and off-road climbs, this matched oxygen sensor set restores factory air-fuel metering on the \u003cstrong\u003eN180\u003c\/strong\u003e platform. Dependable closed-loop feedback keeps your \u003cstrong\u003e5VZ-FE 3.4L V6\u003c\/strong\u003e running clean, efficient, and ready for high-mileage duty.\u003c\/p\u003e","brand":"VelocityMax","offers":[{"title":"Default Title","offer_id":68114817515768,"sku":"DS-ER09UWRJE","price":38.95,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0800\/1290\/2648\/files\/o2-oxygen-sensor-upstream-downstream-for-toyota-4runner-1996-2000-3-4l-1.jpg?v=1794698883","url":"https:\/\/performancechiptuning.com\/products\/o2-oxygen-sensor-upstream-downstream-for-toyota-4runner-1996-2000-3-4l","provider":"Performance Chip Tuning","version":"1.0","type":"link"}