{"product_id":"oxygen-sensors-for-chevrolet-blazer-2003-2005-4-3l-upstream-downstream","title":"Oxygen Sensors for Chevrolet Blazer (2003-2005) 4.3L Upstream \u0026 Downstream","description":"\u003ch2\u003eDirect-Fit Oxygen Sensor Kit for 2003-2005 Chevrolet Blazer\u003c\/h2\u003e\n\n\u003cp\u003e\u003cstrong\u003eWhat it Does:\u003c\/strong\u003e The Direct-Fit Oxygen Sensor Kit replaces degraded upstream and downstream lambda sensors on the 2003-2005 Chevrolet Blazer to restore precise closed-loop air-fuel ratio calculation and clear catalytic efficiency fault codes.\u003c\/p\u003e\n\n\u003ch3\u003eThe Stock Chevrolet Blazer Sensor Degradation and Trim Drift\u003c\/h3\u003e\n\u003cp\u003eAs the factory exhaust system on the \u003cstrong\u003eGMT330\u003c\/strong\u003e platform ages, the stock oxygen sensors suffer from silica glaze, soot accumulation, and repeated thermal shock. Inside the 4.3L \u003cstrong\u003eVortec 4300\u003c\/strong\u003e (\u003cstrong\u003eLU3\u003c\/strong\u003e) exhaust stream, lazy zirconia switching elements fail to toggle rapidly across the stoichiometric 14.7:1 AFR threshold. This signal latency leads to skewed short-term and long-term fuel trims (STFT\/LTFT), inducing unburned hydrocarbon loading, spark plug fouling, degraded fuel economy, and false catalyst efficiency diagnostic trouble codes (such as P0420).\u003c\/p\u003e\n\n\u003ch3\u003eThe Engineering Solution\u003c\/h3\u003e\n\u003cp\u003eThis upstream and downstream kit features high-temperature 304 stainless steel dual-protection covers and porous ceramic diffusion layers designed to resist particulate contamination. Integrated high-output ceramic heating elements accelerate sensor light-off, allowing the powertrain control module to enter closed-loop operation within seconds of engine startup. Direct-fit weather-pack terminal plugs match OEM pinning to prevent voltage drop and harness splicing, preserving critical 0-1V signal fidelity and ensuring consistent exhaust monitoring under severe duty cycles.\u003c\/p\u003e\n\n\u003ch3\u003eTechnical Specifications\u003c\/h3\u003e\n\u003ctable width=\"100%\" style=\"border-collapse: collapse; border: 1px solid #e0e0e0; font-size: 14px; margin-bottom: 20px;\"\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;\"\u003e2003-2005 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;\"\u003e4.3L Vortec 4300 (LU3) \/ 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;\"\u003eStock Output\u003c\/th\u003e\n\u003ctd style=\"padding:10px; border: 1px solid #e0e0e0;\"\u003e190 hp \/ 250 lb-ft\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\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;\"\u003eN\/A\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/table\u003e\n\n\u003ch3\u003eCompatibility\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003e2003 Chevrolet Blazer Base, LS, LT, Trailblazer, Xtreme (4.3L V6 LU3)\u003c\/li\u003e\n  \u003cli\u003e2004 Chevrolet Blazer Base, LS, Xtreme (4.3L V6 LU3)\u003c\/li\u003e\n  \u003cli\u003e2005 Chevrolet Blazer Base, LS, Xtreme (4.3L V6 LU3)\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eFrequently Asked Questions\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003eDoes this fit the GMT330 Blazer?\u003c\/strong\u003e\u003cbr\u003e Yes, this is a direct fit for the 2003-2005 Chevrolet Blazer equipped with the \u003cstrong\u003eLU3\u003c\/strong\u003e 4.3L V6 engine.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWill replacing both sensors clear my check engine light?\u003c\/strong\u003e\u003cbr\u003e Yes, clearing stored ECM trouble codes after installing functional upstream and downstream sensors resolves circuit and fuel trim DTCs.\u003c\/p\u003e\n\n\u003ch3\u003eThe Chevrolet Reliability Standard\u003c\/h3\u003e\n\u003cp\u003eBuilt for the rugged demands of the GMT-series truck and SUV platforms, this oxygen sensor set provides the thermal resilience required to withstand heavy towing, rough off-road vibration, and long-term daily driving without signal loss.\u003c\/p\u003e","brand":"VelocityMax","offers":[{"title":"Default Title","offer_id":50511154839800,"sku":"DS-EJZI3PT4C","price":79.95,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0800\/1290\/2648\/files\/oxygen-sensors-for-chevrolet-blazer-2003-2005-4-3l-upstream-downstream-1.jpg?v=1789410833","url":"https:\/\/performancechiptuning.com\/fr\/products\/oxygen-sensors-for-chevrolet-blazer-2003-2005-4-3l-upstream-downstream","provider":"Performance Chip Tuning","version":"1.0","type":"link"}