follow the plug wires they are on the heads
spark plug
A 2004 Chevrolet Trailblazer that has a 4.2 liter engine will have a spark plug gap of .044 inches. The best spark plugs for this vehicle are iridium spark plugs.
.043
AC Delco iridiums
No.
Remove the spark plug wires from the spark plugs, use an extension for your Allen wrench, and use a spark plug socket to remove the spark plug.
There are not any plugs wires. The Inline six uses coil packs over top of each spark plug.
mike
Spark Plugs, Spark Plug wires, PCV Valve
No, it does not. This year uses a plug & coil configuration, where each plug has its own ignition coil, rather than a wire which runs back to a central coil.
Disconnect the battery, remove the spark plug wires and boots, and remove the old spark plugs. Toss out the old spark plugs, put in the new spark plugs, replace the spark plug wires and boots, and connect the battery.