Spark plugs are fitted on the sides of the engine and for the 2.3L from 1993 to 1997 and the 2.5L from 1998 through 2001 four-cylinder models, there are eight plugs as each cylinder has two spark plugs. Getting to the spark plugs from the intake manifold side is tight and may call for detachment of the intake system and the use of tools. The manufacturer as usual gives a maximum replace interval for spark plugs depending on the engine model, which is about 60,000 miles for the latest models due to misfiring before the 100,000 mark. A socket late with numerous extensions, a gap gauge, and an optionally plug wire removal tool are required equipment for spark plug replacement. It is useful to buy replacement plugs ahead of time and pre-gap them to the correct size and to replace them in sets, using the plugs that are required in accordance with the Vehicle Emission Control Information label. Engine should be allowed to cool down before removal, and even the new plugs should be checked for faults. Periodically it should be checked with a gauge and if there is need for some bending, it should be done carefully to avoid damaging the side electrode. The plugs are available only for 2011 4.0L-V6 models, and the right front wheel has to be taken off in order to get to the plugs. When you are disconnecting the spark plug wires, make sure that you pull the boot only and then blow the debris using the compressed air in the hole for spark plug. After its withdrawal, such a plug has to be matched with a condition chart that reflects the engine's performance. New plugs should be threaded in by hand and tightened with torque wrench Tightening plugs-Rubber hose can be used as a tool and should be placed in a manner that it will not allow cross threading. Following twisting every plug, check and connect the plug wire and apply silicone dielectric compound on the inside of every boot before tightening. Cables of spark plugs should be inspected to see if there is any damage on them, any bad cables should be changed and when replacing them one should ensure that they connect them in the proper manner. On the 1993 and 1994 3.0L engine, the distributor cap is located at the rear of the engine, and will look like the cap and rotor showed here; the cap and rotor should be examined for cracks, carbon tracks, and corrosion, and replaced as needed. When replacing the cap, connect the spark plug wires one by one in order to avoid confusion, and after properly aligning make sure it is tightened.