{"product_id":"ignition-coil-spark-plugs-for-gmc-sierra-1999-2007-4-3l","title":"Ignition Coil + Spark Plugs for GMC Sierra (1999-2007) 4.3L","description":"\u003ch2 style=\"font-size: clamp(18px, 3vw, 21px); margin-bottom: 15px; line-height: 1.3;\"\u003eHigh-Output Ignition Coil and Spark Plug Service Kit for 1999-2007 GMC Sierra (GMT800)\u003c\/h2\u003e\n\n\u003cp\u003e\u003cstrong\u003eWhat it Does:\u003c\/strong\u003e The direct-fit Ignition Coil and Spark Plug Kit restores primary saturation and secondary ignition voltage on the 1999-2007 Sierra 4.3L to eliminate misfires, stabilize idle, and restore combustion efficiency.\u003c\/p\u003e\n\n\u003ch3\u003eThe Stock GMC Sierra Secondary Voltage Degradation\u003c\/h3\u003e\n\u003cp\u003eUnder-hood thermal cycling on the \u003cstrong\u003eGMT800\u003c\/strong\u003e platform degrades the factory ignition coil over time. The primary failure point is internal epoxy insulation breakdown, resulting in micro-arcing and secondary winding collapse under heavy load. Concurrently, prolonged spark plug operation erodes center electrodes and widens factory gaps, forcing the aged coil to generate higher strike voltages than its insulation can manage. This leads to erratic spark kernel formation, intermittent P0300 multi-cylinder misfires, unburnt hydrocarbon fouling, and noticeable power sag during towing or grade climbing.\u003c\/p\u003e\n\n\u003ch3\u003eThe Engineering Solution\u003c\/h3\u003e\n\u003cp\u003eThis replacement ignition kit provides complete secondary ignition renewal engineered to factory resistance specifications. The ignition coil is constructed with high-dielectric epoxy potting that resists vibration and prevents internal voltage leakage under extreme thermal loads. Paired with fresh direct-gap spark plugs, the assembly ensures stable secondary kilovolt output across the entire RPM range. This precise ignition energy reduces coil rise time, restores immediate throttle response, and preserves the lifespan of downstream catalytic converters on the \u003cstrong\u003eVortec 4300\u003c\/strong\u003e engine.\u003c\/p\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;\"\u003e1999-2007 GMC Sierra 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;\"\u003e\n\u003cstrong\u003eVortec 4300 (LU3 \/ L35)\u003c\/strong\u003e \/ \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;\"\u003e200 hp \/ 260 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\n\u003cstrong\u003e10489421\u003c\/strong\u003e, \u003cstrong\u003e19207138\u003c\/strong\u003e, \u003cstrong\u003e19418996\u003c\/strong\u003e, \u003cstrong\u003eD577\u003c\/strong\u003e, \u003cstrong\u003eDR49\u003c\/strong\u003e\n\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\u003e1999-2006 GMC Sierra 1500 4.3L V6\u003c\/li\u003e\n  \u003cli\u003e2007 GMC Sierra 1500 Classic 4.3L V6\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eFrequently Asked Questions\u003c\/h3\u003e\n\u003ch4\u003eDoes this fit the GMT800 Sierra?\u003c\/h4\u003e\n\u003cp\u003eYes, this is a direct fit for the 1999-2007 GMC Sierra equipped with the \u003cstrong\u003eVortec 4300\u003c\/strong\u003e engine.\u003c\/p\u003e\n\n\u003ch4\u003eWhy does this kit include eight spark plugs for a V6 engine?\u003c\/h4\u003e\n\u003cp\u003eThe kit supplies eight direct-fit plugs to provide two spare units, requiring only six to complete a full service on the 4.3L V6.\u003c\/p\u003e\n\n\u003ch3\u003eThe GMC Workhorse Caliber\u003c\/h3\u003e\n\u003cp\u003eFor trucks relied upon for hauling and job-site utility, dependable ignition performance is non-negotiable for maintaining maximum low-end torque and ensuring reliable cold-weather starts.\u003c\/p\u003e","brand":"VelocityMax","offers":[{"title":"Default Title","offer_id":67518823104760,"sku":"DS-E7J4ITYDM","price":74.95,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0800\/1290\/2648\/files\/ignition-coil-spark-plugs-for-gmc-sierra-1999-2007-4-3l-1.jpg?v=1790370622","url":"https:\/\/performancechiptuning.com\/products\/ignition-coil-spark-plugs-for-gmc-sierra-1999-2007-4-3l","provider":"Performance Chip Tuning","version":"1.0","type":"link"}