{"product_id":"o2-oxygen-sensor-upstream-downstream-for-gmc-sierra-1500-yukon-2003-2005-4-8l","title":"O2 Oxygen Sensor Upstream Downstream for GMC Sierra 1500, Yukon (2003-2005) 4.8L","description":"\u003ch2 style=\"font-size: clamp(18px, 3vw, 21px); margin-bottom: 15px; line-height: 1.3;\"\u003eDirect-Fit Replacement Oxygen Sensor Set for 2003-2005 GMC Sierra 1500, Yukon (GMT800)\u003c\/h2\u003e\n\n\u003cp\u003e\u003cstrong\u003eWhat it Does:\u003c\/strong\u003e The 4-piece Oxygen Sensor Set replaces worn factory sensors on the 2003-2005 GMC Sierra 1500 and Yukon to restore precise closed-loop air-fuel ratios, eliminate hesitation, and maximize fuel efficiency.\u003c\/p\u003e\n\n\u003ch3\u003eThe Stock GMC Sierra 1500, Yukon Sensor Failure Modes\u003c\/h3\u003e\n\u003cp\u003eFactory exhaust sensors in the \u003cstrong\u003eGMT800\u003c\/strong\u003e chassis endure extreme thermal cycling, carbon blow-by, and environmental contamination. Over time, the internal zirconia sensing elements become poisoned by unburnt hydrocarbons and silicone blow-by, leading to sluggish voltage switching. This sensor lag forces the powertrain control module (PCM) into poor fuel trim calculations, resulting in rich-running conditions, fouled spark plugs, failed smog inspections, and persistent diagnostic trouble codes including \u003cstrong\u003eP0130\u003c\/strong\u003e, \u003cstrong\u003eP0161\u003c\/strong\u003e, \u003cstrong\u003eP0420\u003c\/strong\u003e, and \u003cstrong\u003eP0430\u003c\/strong\u003e.\u003c\/p\u003e\n\n\u003ch3\u003eThe Engineering Solution\u003c\/h3\u003e\n\u003cp\u003eEngineered to original equipment tolerances, this comprehensive 4-sensor package restores both upstream mixture regulation and downstream catalyst monitoring. Built with laser-welded stainless steel bodies, porous ceramic diffusion barriers, and dual-layer protective shielding, these sensors resist thermal shock and mechanical vibration under heavy loads. Pre-calibrated factory pigtails and OE-spec weather-pack connectors ensure exact harness length routing away from blistering exhaust manifold heat without splicing or pin modifications.\u003c\/p\u003e\n\n\u003ch3\u003eWhat's Included\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003e2 Upstream Oxygen Sensors\u003c\/li\u003e\n  \u003cli\u003e2 Downstream Oxygen Sensors\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eTechnical Specifications\u003c\/h3\u003e\n\u003cdiv style=\"overflow-x: auto; margin-bottom: 20px;\"\u003e\n  \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;\"\u003e2003-2005 GMC Sierra 1500, Yukon\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;\"\u003e4.8L Vortec \u003cstrong\u003eLR4\u003c\/strong\u003e V8 \/ \u003cstrong\u003eGMT800\u003c\/strong\u003e\n\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;\"\u003e285 hp \/ 295 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;\"\u003e\u003cstrong\u003e234-4407\u003c\/strong\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003c\/table\u003e\n\u003c\/div\u003e\n\n\u003ch3\u003eCompatibility\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003e2003-2005 GMC Sierra 1500 4.8L V8\u003c\/li\u003e\n  \u003cli\u003e2003-2005 GMC Yukon 4.8L V8\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eFrequently Asked Questions \u0026amp; Fitment Warnings\u003c\/h3\u003e\n\u003ch4\u003eDoes this fit the GMT800 Sierra 1500, Yukon?\u003c\/h4\u003e\n\u003cp\u003eYes, this is a direct fit for the 2003-2005 GMC Sierra 1500 and Yukon equipped with the 4.8L \u003cstrong\u003eLR4\u003c\/strong\u003e Vortec engine; always verify harness connector style before installing.\u003c\/p\u003e\n\n\u003ch4\u003eShould anti-seize compound be used during installation?\u003c\/h4\u003e\n\u003cp\u003eApply anti-seize exclusively to the threaded housing while ensuring none contacts the active sensor element, and clear stored ECM codes after securing wiring harness clips.\u003c\/p\u003e\n\n\u003ch3\u003eThe GMC Heavy-Duty Reliability Standard\u003c\/h3\u003e\n\u003cp\u003eBuilt for rigorous towing, heavy payload hauling, and everyday dependability, these sensors restore the rapid telemetry your truck needs to maintain safe exhaust gas temperatures and optimal towing performance.\u003c\/p\u003e","brand":"VelocityMax","offers":[{"title":"Default Title","offer_id":67910904611064,"sku":"DS-E7ZL9T2BC","price":90.95,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0800\/1290\/2648\/files\/o2-oxygen-sensor-upstream-downstream-for-gmc-sierra-1500-yukon-2003-2005-4-8l-1.jpg?v=1793393125","url":"https:\/\/performancechiptuning.com\/de\/products\/o2-oxygen-sensor-upstream-downstream-for-gmc-sierra-1500-yukon-2003-2005-4-8l","provider":"Performance Chip Tuning","version":"1.0","type":"link"}