The spark plugs on a 1997 Chevrolet Blazer perform the same function as they do on any engine; they provide the spark for the combustion system to work correctly. Changing the plugs on the engine follows the same procedure as on any other vehicle, but the main problem is accessing the plugs, since the 4.3l V6 engine is tightly packed into the engine compartment, and getting in there can be tough. But with the right combination of tools, you can get them out and chang them correctly.
Allow the engine to cool for 2 to 5 hours prior to working on the spark plug system. Pop the hood and locate the spark plugs, which are on the cylinder heads on either side of the vehicle next to the exhaust manifold. Choose a spark plug to replace and grip the boot on the spark plug wire with your hands. Remove the wire from the plug with a twisting motion as you pull it out.
Remove the stock spark plug using the 3/8-inch ratchet, extension and spark plug socket. If it's difficult to access, use the 3/8-inch universal joint between either the extension and the socket or the extension and the ratchet to provide extra movement. Discard the spark plug.
Gap the replacement spark plugs to .060 using the spark plug gapping tool.
Hand-thread a replacement spark plug into the cylinder head, then tighten it in place using the 3/8-inch ratchet, extension and spark plug socket. Then press the spark plug wire onto the spark plug until it makes a popping noise, indicating it's locked in place.
Repeat steps 1 through 4 for the remaining spark plugs, moving systematically from one plug to the other so you don't lose track of which plugs have been replaced, and so that you don't cross any spark plug wires.
