Dirty spark plugs can occur on any make, model, or year. Changing the spark plugs should be done for maintenance, such as when you do a tune up.
Cheap ones run for $2. Premium Bosch plugs run for about $6 a piece.
No.
are the spark plugs old they may have to be changed
Pass side front to back 2-4-6-8 driver side 1-3-5-7
bad plugs
Beneath their coils.
Changing the spark plugs is a relatively easy job which can be done by anybody with slight mechanical knowledge. On a Jeep with the 4.7L engine, the intake needs to be removed. The coilpacks can then be removed, and then the spark plugs can be removed and replaced with new ones. The job should take about 1-2 hours. See the related link below for detailed instructions.
Depending on your year of Cherokee, I know the 1991 and newer Cherokees use Champion RC12LYC, Autolite 985, and Denso QJ16HR-U with the 4.0L 6 cylinder engine. On my 2000 Jeep Grand Cherokee Limited with a 4.7L V8, I used Champion Copper Plus RC12MCC4. These are the plugs that the manufacturer calls for. No other plugs should be used. (If you don't believe me, search the internet) Learn how to change the spark plugs on a 4.7L V8 (SEE LINK BELOW).
At the top of the engine. The intake needs to be removed to access the plugs on the drivers side. Since there are no spark plug wires, the coil packs need to be removed. The plugs can then be removed and replaced with new ones. See the link below for detailed instructions.
There are three on the left, three on the right, and two on the rear.
They are under the coils, next to the fuel injectors.