{"product_id":"o2-oxygen-sensor-upstream-downstream-for-chevrolet-blazer-1996-2001-4-3l","title":"O2 Oxygen Sensor Upstream Downstream for Chevrolet Blazer (1996-2001) 4.3L","description":"\u003ch2 style=\"font-size: clamp(18px, 3vw, 21px); margin-bottom: 15px; line-height: 1.3;\"\u003eDirect-Fit Upstream \u0026amp; Downstream O2 Oxygen Sensor Kit for 1996-2001 Chevrolet Blazer (GMT330)\u003c\/h2\u003e\u003cp\u003e\u003cstrong\u003eWhat it Does:\u003c\/strong\u003e This matched 3-piece upstream and downstream oxygen sensor kit restores closed-loop air-fuel ratio monitoring and catalytic converter efficiency checks on the 1996-2001 Chevrolet Blazer \u003cstrong\u003eGMT330\u003c\/strong\u003e powered by the \u003cstrong\u003eL35 4.3L Vortec V6\u003c\/strong\u003e.\u003c\/p\u003e\u003ch3\u003eThe Stock Chevrolet Blazer Sensor Degradation\u003c\/h3\u003e\u003cp\u003eFactory oxygen sensors on the \u003cstrong\u003eGMT330\u003c\/strong\u003e Blazer with the \u003cstrong\u003eL35 4.3L Vortec V6\u003c\/strong\u003e endure constant thermal cycling and exhaust soot contamination. Over time, silica poisoning, trace coolant exposure, or oil ash foul the zirconia sensing element, slowing voltage switching between rich and lean states. Simultaneously, the internal heating element degrades, delaying closed-loop operation and forcing the PCM to run an overly rich base fuel map. This sensor sluggishness commonly triggers \u003cstrong\u003eP0133\u003c\/strong\u003e, \u003cstrong\u003eP0134\u003c\/strong\u003e, \u003cstrong\u003eP0140\u003c\/strong\u003e, or \u003cstrong\u003eP0171\u003c\/strong\u003e\/\u003cstrong\u003eP0174\u003c\/strong\u003e fuel trim fault codes.\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 Slow response or heater circuit faults like \u003cstrong\u003eP0133\u003c\/strong\u003e, \u003cstrong\u003eP0135\u003c\/strong\u003e, and \u003cstrong\u003eP0141\u003c\/strong\u003e illuminate the MIL when voltage transitions fall out of spec.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eRich Exhaust \u0026amp; Rough Idle:\u003c\/strong\u003e Biased lean readings cause the PCM to command excess fuel, resulting in raw fuel odor, fouled spark plugs, and unstable idle.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDropped MPG \u0026amp; Failed Emissions:\u003c\/strong\u003e Prolonged open-loop fueling cuts highway fuel economy and increases hydrocarbon and CO tailpipe output.\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eThe Direct-Fit 4-Wire Heated Zirconia Solution\u003c\/h3\u003e\u003cp\u003eThis matched kit replaces both pre-cat bank sensors and the post-cat monitor simultaneously using OEM-spec \u003cstrong\u003e4-wire heated zirconia\u003c\/strong\u003e elements. Each sensor features a laser-welded \u003cstrong\u003estainless steel\u003c\/strong\u003e body and porous PTFE protection shield to resist thermal shock, moisture intrusion, and exhaust contamination. Factory-matched pigtail lengths and keyed weatherproof connectors eliminate wire splicing or circuit resistance mismatches. By restoring rapid 0.1V-to-0.9V switching across all three bungs, the \u003cstrong\u003eL35 4.3L Vortec V6\u003c\/strong\u003e PCM maintains crisp stoichiometric fuel control.\u003c\/p\u003e\u003ch3\u003eWhat's Included\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e2 Upstream Oxygen Sensors\u003c\/li\u003e\n\u003cli\u003e1 Downstream Oxygen Sensor\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;\"\u003e1996-2001 Chevrolet Blazer\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;\"\u003eL35 4.3L Vortec V6 \/ GMT330\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;\"\u003eSensor Architecture\u003c\/th\u003e\n\u003ctd style=\"padding:10px; border: 1px solid #e0e0e0;\"\u003e4-Wire Heated Zirconia \/ Direct-Fit OEM Harness\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 Thread-In OEM Replacement (No Cutting or Splicing)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/table\u003e\u003c\/div\u003e\u003ch3\u003eCompatibility\u003c\/h3\u003e\u003cul\u003e\u003cli\u003e1996-2001 Chevrolet Blazer 4.3L\u003c\/li\u003e\u003c\/ul\u003e\u003ch3\u003eFrequently Asked Questions \u0026amp; Fitment Warnings\u003c\/h3\u003e\u003ch4\u003eDoes this fit the GMT330 Blazer?\u003c\/h4\u003e\u003cp\u003e\u003cstrong\u003eYes.\u003c\/strong\u003e This is a direct fit for the 1996-2001 Chevrolet Blazer equipped with the \u003cstrong\u003eL35 4.3L Vortec V6\u003c\/strong\u003e engine. \u003cstrong\u003eVerify your engine displacement and 3-sensor exhaust configuration before ordering, as alternate 4-sensor layouts differ.\u003c\/strong\u003e\u003c\/p\u003e\u003ch4\u003eWill this clear P0133, P0135, or P0141 codes?\u003c\/h4\u003e\u003cp\u003e\u003cstrong\u003eYes.\u003c\/strong\u003e Replacing both upstream sensors and the downstream monitor resolves heater circuit faults and sluggish voltage switching that trigger \u003cstrong\u003eP0133\u003c\/strong\u003e, \u003cstrong\u003eP0135\u003c\/strong\u003e, \u003cstrong\u003eP0140\u003c\/strong\u003e, and \u003cstrong\u003eP0141\u003c\/strong\u003e. \u003cstrong\u003eClear stored DTCs and inspect exhaust manifolds for leaks prior to road testing.\u003c\/strong\u003e\u003c\/p\u003e\u003ch4\u003eAre splicing tools required for installation?\u003c\/h4\u003e\u003cp\u003e\u003cstrong\u003eNo splicing is required.\u003c\/strong\u003e All three sensors use factory-terminated OEM connectors for plug-and-play installation into the \u003cstrong\u003eGMT330\u003c\/strong\u003e harness. \u003cstrong\u003eUse an oxygen sensor socket and ensure threads are clean before torquing to factory specification.\u003c\/strong\u003e\u003c\/p\u003e\u003ch3\u003eThe Chevrolet Heavy-Duty Standard\u003c\/h3\u003e\u003cp\u003eBuilt for the thermal demands of daily driving, towing, and off-road duty in the \u003cstrong\u003eGMT330\u003c\/strong\u003e platform, this matched sensor set restores factory fuel trim accuracy. Expect dependable closed-loop operation, cleaner combustion, and consistent CEL-free performance.\u003c\/p\u003e","brand":"VelocityMax","offers":[{"title":"Default Title","offer_id":68115812417784,"sku":"DS-EQ6PROJJX","price":57.95,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0800\/1290\/2648\/files\/o2-oxygen-sensor-upstream-downstream-for-chevrolet-blazer-1996-2001-4-3l-1.jpg?v=1794709312","url":"https:\/\/performancechiptuning.com\/products\/o2-oxygen-sensor-upstream-downstream-for-chevrolet-blazer-1996-2001-4-3l","provider":"Performance Chip Tuning","version":"1.0","type":"link"}