How to Replace the Spark Plugs in a 2002 Jeep Grand Cherokee Laredo

by Cayden Conor
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The spark plugs on the 2002 Jeep Grand Cherokee Laredo should be changed every 30,000 miles. Plugs become cold-fouled -- often referred to as carbon-fouled. This usually happens if one or more of the wires are defective, if the air cleaner element is clogged or you drive only short distances. Leaking valve guide seals, worn piston rings and cylinder wear also foul plugs. Over time, the gap gets bigger on the electrodes -- this is normal wear and tear, but the plugs must be replaced to ensure proper running conditions.

Step 1

Unplug the wiring harness connectors from the coils by pushing downward on the release lock on the top of the connector, then pull the connector off the coil. Unbolt the coils, using the appropriate socket, then pull the coil off the plug.

Step 2

Blow air around the spark plug, ensuring all debris is removed from the base of the plug, so it doesn't fall into the cylinders.

Step 3

Remove the spark plug, using the spark plug socket.

Step 4

Insert the new spark plug, and screw it into the head by hand as far as you can. Tighten the plug firmly, but no more than 28 foot-pounds of torque. The torque wrench is not necessary, as long as you don't over-tighten the plugs.

Step 5

Reinstall the coil, and tighten the retaining bolt firmly. Plug in the wiring harness connector. Repeat for all plugs.

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