{"product_id":"o2-oxygen-sensor-upstream-downstream-for-chevrolet-silverado-1999-2002-4-3l-4-8l-5-3l","title":"O2 Oxygen Sensor Upstream Downstream for Chevrolet Silverado (1999-2002) 4.3L 4.8L 5.3L","description":"\u003ch2 style=\"font-size: clamp(18px, 3vw, 21px); margin-bottom: 15px; line-height: 1.3;\"\u003eDirect-Fit O2 Oxygen Sensor Kit for 1999-2002 Chevrolet Silverado (GMT800)\u003c\/h2\u003e\u003cp\u003e\u003cstrong\u003eWhat it Does:\u003c\/strong\u003e This 4-piece upstream and downstream oxygen sensor kit monitors pre- and post-catalyst exhaust oxygen levels on 1999-2002 Chevrolet Silverado 1500 (\u003cstrong\u003eGMT800\u003c\/strong\u003e) \u003cstrong\u003e4.3L (VIN W)\u003c\/strong\u003e, \u003cstrong\u003e4.8L (LR4)\u003c\/strong\u003e, and \u003cstrong\u003e5.3L (LM7)\u003c\/strong\u003e engines to maintain closed-loop fuel trim accuracy.\u003c\/p\u003e\u003ch3\u003eThe Stock Chevrolet Silverado Sensor Failure\u003c\/h3\u003e\u003cp\u003eOver high mileage on the \u003cstrong\u003eGMT800\u003c\/strong\u003e platform, factory zirconia O2 sensors on the \u003cstrong\u003e4.3L (L35 VIN W)\u003c\/strong\u003e, \u003cstrong\u003e4.8L (LR4)\u003c\/strong\u003e, and \u003cstrong\u003e5.3L (LM7)\u003c\/strong\u003e engines suffer from thermal fatigue, carbon fouling, and internal heater burnout. Exhaust moisture and oil vapor corrode the sensing element, slowing voltage switching between 0.1V and 0.9V. When the PCM detects sluggish cross-counts or open heater resistance, it disables closed-loop fueling and triggers codes like \u003cstrong\u003eP0135\u003c\/strong\u003e, \u003cstrong\u003eP0141\u003c\/strong\u003e, \u003cstrong\u003eP0171\u003c\/strong\u003e, and \u003cstrong\u003eP0174\u003c\/strong\u003e.\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 \/ Heater DTCs:\u003c\/strong\u003e Codes like \u003cstrong\u003eP0135\u003c\/strong\u003e, \u003cstrong\u003eP0141\u003c\/strong\u003e, or lean trim faults \u003cstrong\u003eP0171\/P0174\u003c\/strong\u003e trigger when internal heater coils fail or sensor response lags.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eRich Running \u0026amp; Rough Idle:\u003c\/strong\u003e Slow upstream voltage switching forces rich open-loop fueling, fouling spark plugs and increasing tailpipe soot.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFuel Economy Loss \u0026amp; Failed Emissions:\u003c\/strong\u003e Inaccurate air-fuel feedback reduces towing MPG and prevents OBD-II readiness monitors from setting.\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eThe Direct-Fit O2 Sensor Solution\u003c\/h3\u003e\u003cp\u003eReplacing all four sensors as a matched set restores balanced Bank 1 and Bank 2 fuel trim feedback across the \u003cstrong\u003eGMT800\u003c\/strong\u003e exhaust system. Each direct-fit sensor uses a fast-acting heated zirconia element inside a laser-welded stainless steel housing to resist thermal shock and moisture. Factory-length heat-shielded harnesses and OE-style weather-pack connectors eliminate splicing, delivering clean millivolt signals to the PCM and bolt-in installation into stock M18x1.5 exhaust bungs.\u003c\/p\u003e\u003ch3\u003eWhat's Included\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e2 Upstream Oxygen Sensors\u003c\/li\u003e\n\u003cli\u003e2 Downstream Oxygen Sensors\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;\"\u003e1999-2002 Chevrolet Silverado 1500\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 (L35 VIN W), 4.8L (LR4), 5.3L (LM7) \/ GMT800\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 Narrowband (Upstream \u0026amp; Downstream)\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\u003c\/table\u003e\u003c\/div\u003e\u003ch3\u003eCompatibility\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e1999-2002 Chevrolet Silverado 1500 4.3L (VIN W)\u003c\/li\u003e\n\u003cli\u003e1999-2002 Chevrolet Silverado 1500 4.8L (Confirm build and VIN; some 2000-2002 applications exclude Canada-built trucks)\u003c\/li\u003e\n\u003cli\u003e1999-2002 Chevrolet Silverado 1500 5.3L (Confirm build and VIN; some 2000-2002 applications exclude Canada-built trucks)\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eFrequently Asked Questions \u0026amp; Fitment Warnings\u003c\/h3\u003e\u003ch4\u003eDoes this fit the GMT800 Silverado?\u003c\/h4\u003e\u003cp\u003e\u003cstrong\u003eYes.\u003c\/strong\u003e This is a direct fit for the 1999-2002 Chevrolet Silverado 1500 equipped with the \u003cstrong\u003e4.3L (VIN W)\u003c\/strong\u003e, \u003cstrong\u003e4.8L (LR4)\u003c\/strong\u003e, or \u003cstrong\u003e5.3L (LM7)\u003c\/strong\u003e engine. \u003cstrong\u003eSome 2000-2002 4.8L and 5.3L applications exclude Canada-built trucks—confirm your build and VIN before ordering; Escalade, Tahoe, Suburban, Express, and GMC applications are omitted.\u003c\/strong\u003e\u003c\/p\u003e\u003ch4\u003eWill this clear P0135, P0141, or P0171\/P0174 codes?\u003c\/h4\u003e\u003cp\u003e\u003cstrong\u003eYes, when triggered by worn or open-heater OEM sensors.\u003c\/strong\u003e Replacing all four sensors restores proper heater resistance and closed-loop cross-counts across \u003cstrong\u003eGMT800\u003c\/strong\u003e Bank 1 and Bank 2 manifolds.\u003c\/p\u003e\u003ch4\u003eAre both upstream and downstream sensors ready to install?\u003c\/h4\u003e\u003cp\u003e\u003cstrong\u003eYes.\u003c\/strong\u003e All four direct-fit sensors include OE-style connectors; inspect exhaust bung threads before torquing and keep anti-seize strictly off the sensor tip.\u003c\/p\u003e\u003ch3\u003eThe Chevrolet Heavy-Duty Standard\u003c\/h3\u003e\u003cp\u003eBuilt for the thermal loads of towing and high-mileage hauling, this matched sensor set keeps your \u003cstrong\u003eGMT800\u003c\/strong\u003e Silverado operating at factory air-fuel precision. Restore consistent fuel mileage and reliable closed-loop engine management.\u003c\/p\u003e","brand":"VelocityMax","offers":[{"title":"Default Title","offer_id":68116151828728,"sku":"DS-ENDUAV9M4","price":58.95,"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-silverado-1999-2002-4-3l-4-8l-5-3l-1.jpg?v=1794710926","url":"https:\/\/performancechiptuning.com\/products\/o2-oxygen-sensor-upstream-downstream-for-chevrolet-silverado-1999-2002-4-3l-4-8l-5-3l","provider":"Performance Chip Tuning","version":"1.0","type":"link"}