Your 1995 Mercury Cougar XR7’s spark plugs provide spark to the engine. Without them, your Cougar would not run. The Cougar uses an ignition system without a distributor. Instead of a power distributor, coil packs are used to provide spark to the engine. Over time, the ends of these plugs will erode away and the entire plug will need to be replaced. Replacement spark plugs are normally available from most auto-parts stores, and you can replace them every 30,000 miles, though high-end spark plugs could have a service life of 60,000 miles or more.
Tools Used: Tools, Replacement spark plugs, Socket wrench, Socket set, Phillips screwdriver, Spark-plug socket, Pliers
Replace Spark Plugs
Open the hood and unbolt the engine cover bolts and remove the engine cover. Remove the EGR solenoid from the upper intake manifold using a pair of pliers. Pull it straight out of the intake manifold. You might need to twist it slightly back and forth to get it to come out. The EGR solenoid will look like a large rubber stopper stuck into the intake manifold.
Disconnect the coil-over-plug electrical connectors on the coil packs. Squeeze the locking tabs on the spark-plug wire ends and pull them out of the engine. Only work on one spark-plug wire at a time (only pull out one plug at a time while changing the spark plugs to avoid mixing up the firing order of the engine).
Unbolt the spark plugs using a socket wrench, socket extension and the spark-plug socket. Lower the new spark plug into the plug well, hand-thread the plug for the first few threads, and then tighten with a socket wrench. Installation is the reverse of removal.