How to Change the Ignition Coil on a GMC 1998 Sierra

In 1962, GMC, along with sister company Chevrolet, released the C- and K-series of pickups. In this series, the C indicated a two-wheel-drive truck and a K indicated a four-wheel-drive truck. In 1995, the Sierra name made its debut in the GMC lineup of full-size pickups, but GMC only used it to indicate trim levels: Sierra, Sierra Grande, High Sierra and Sierra Classic. The 1998 model year GMC C1500 Sierra came standard with a 4.3-liter engine that used an electronic ignition system to deliver electricity to the spark plugs. Replacing the ignition coil in the 4.3-liter engine is a straightforward task, but you must remove the air cleaner and its outlet hose to access it.

Instructions

1

Loosen the hose clamp at both ends of the flexible part of the air filter outlet duct, using a Phillips-head screwdriver. Pull the flexible duct from the air filter box and the hard-formed air intake tube the tube leading to the throttle body.

2

Remove the bolt, which is under the air filter box, using a ratchet and socket. Squeeze and hold the two ears on the air filter boxs intake duct the tube that goes into the fender to release it, and sharply pull the air filter box upward to free it. Set aside the air filter box.

3

Find the ignition coil-and-coil module assembly on the passengers side rear of the engine. Pry upward and hold the locking tab on the wiring harness plugged into the coil. Using a flat-head screwdriver, unplug the wiring harness. Pry upward on the locking tab on the coil modules wiring harness and unplug it.

4

Grab the thick rubber boot on the end of the ignition wire that is plugged into the top of the ignition coil. Pull upward on the rubber boot with a slight twisting motion to unplug the ignition wire.

5

Remove the two bolts securing the ignition coil-and-module bracket to the intake manifold, using a ratchet and socket, and remove the ignition coil-and-coil module assembly, along with its bracket, from the engine.

6

Select a drill bit that is slightly larger in diameter than the center pin in the two rivets securing the ignition coil to its bracket. Drill the center pin from the rivets to remove them, using the selected drill bit and an electric drill. If needed, drive the rivets out with a center punch and a light hammer. Pull the ignition coil from its bracket.

7

Slide the new coil into its bracket, aligning the holes on the base of the coil with the holes in the bracket. Secure the coil in the bracket by installing the two screws that came with the new coil, using a Phillips-head screwdriver.

8

Reinstall the ignition coil-and-coil module assembly onto the intake manifold and hand-tighten their retaining bolts. Torque the retaining bolts to 8 foot-pounds with a torque wrench and socket.

9

Line up the ignition wire boot with its receptacle on top of the new coil and press the wires boot downward until you feel it click into place. Plug the wiring harnesses into their respective receptacle on the coil-and-coil module.

10

Position the air filter box into place in the engine compartment and align its intake tube with the hole in the fender. Press the air filter box toward the fender until the tube clicks into place. Press downward to seat the air filter box on its mount.

11

Thread the bolt into the underside of the air filter box by hand, then torque it to 13 foot-pounds with a torque wrench and socket.

12

Reconnect the flexible air filter outlet hose to the outlet on the air filter box and the inlet on the hard-formed air intake tube. Tighten the two hose clamps with a Phillips-head screwdriver to secure the flexible hose.