What type of spark plugs should you use in a 2000 Jeep Wrangler 4.0?

The 2000 Jeep Wrangler 4.0L uses a Champion RC12YC spark plug, or its equivalent. Many other brands make a functionally equivalent plug, so you can use those as well, but make sure the heat range and thread size are the same. Always check your owner's manual for the manufacturer's specific recommendation.