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Recipe - GM 8.1L / 6.0L Vortec Gasoline (HD 2001-2007, Express/Savana vans incl.)

Specific Fix build

Reliability tier: aggregated - verify before ordering, see /disclosure/

Ignition service path (Ignition service at mileage: coils, wires, plugs (misfire under load)): misfire under load / rough idle at mileage on the 2001-2007 HD gas engines. Isolate the cylinder, swap-test the coil, inspect leads for arcing, then service with the engine-correct PN line: the small block (6.0L) shares the 4.8/5.3 line (plat plug 19299585, coil kits 19418992/19418993, wire kits 19417606/19351572) while the 8.1L big block has its own line (plug 12679800, coil 12570553, wire kits 19417609 2003-2007 and 88892832 2001-2002).

Parts

• 6.0L Vortec Spark Plug (OEM) - plat-tipped plugs, 6.0L small-block line (shared 4.8/5.3) (qty 8)
• 8.1L Vortec Spark Plug (OEM) - the 8.1L plug line - distinct thread/reach from the small block (qty 8)
• 6.0L Vortec Ignition Coil Kit (OEM) - coil kit for the 6.0L line (qty 1)
• GM Truck V8 Ignition Coil (shared 4.8-8.1 line) (OEM) - the coil PN that serves BOTH platform engines per card fitment (qty 1)
• 8.1L Vortec Ignition Coil 1st Design (OEM) - 8.1L 1st-design coil (2003-2005 window); shared 19418993 line covers the rest (qty 1)
• 6.0L Vortec Spark Plug Wire Kit (OEM) - 6.0L wire kit (1st/2nd design PNs aliased) (qty 1)
• 8.1L Vortec Spark Plug Wire Kit 2003-2007 (OEM) - 8.1L wire kit 2003-2007 (qty 1)
• 8.1L Vortec Spark Plug Wire Kit 2001-2002 (OEM) - 8.1L wire kit 2001-2002 (year split per cards) (qty 1)

Install order

1. isolate the misfiring cylinder; swap-test the coil
2. inspect leads for arcing/tracking (dark)
3. service plugs at interval, gapped per engine
4. replace coils/leads per findings

Expected outcome

smooth idle, no misfire under load, plug/lead wear reset to interval

Do not

• do not fit the small-block plugs to the 8.1L (different plug line) or vice versa
• do not replace all coils on one cylinder's complaint - swap-test first
• do not gap plugs by feel on these heads - the spec matters

Parts budget

About $65-$150 in parts. It depends on what the diagnosis finds; each option below is what you buy together. Prices marked "at Dave's" are Dave's Auto Center's, the same as in his store; the others are approximate prices from OEM and maker catalogs, rounded (a manufacturer's list price can run higher). Parts only, no labor.

• about $80: 8 × 6.0L Vortec Spark Plug (OEM) (about $10)
• about $80: 8 × 8.1L Vortec Spark Plug (OEM) (about $10)
• about $95: 6.0L Vortec Ignition Coil Kit (OEM) (about $95)
• about $65: GM Truck V8 Ignition Coil (shared 4.8-8.1 line) (OEM) (about $65)
• about $110: 8.1L Vortec Ignition Coil 1st Design (OEM) (about $110)
• about $75: 6.0L Vortec Spark Plug Wire Kit (OEM) (about $75)
• about $140: 8.1L Vortec Spark Plug Wire Kit 2003-2007 (OEM) (about $140)
• about $150: 8.1L Vortec Spark Plug Wire Kit 2001-2002 (OEM) (about $150)

DIY or shop: DIY-friendly: plugs/wires/coils are hand-tool work on both engines.