The spark plug is one of the most important components in the Subaru Forester engine. It controls the flow of electricity from the distributor cap and sends a charge into the cylinder. The spark then ignites the fuel, driving the piston back down for the next revolution. The combustion process in the gas engine cannot complete itself without the spark. If there is a noticeable decline in your engine performance or it seems you are using more gas than normal, it is probably time to change the plugs.
Things You’ll Need: Feeler gauge, Wrench set, Flat-tip screwdriver, Socket set, Spark plug socket, Socket extension, Socket universal joint, Torque wrench
- Check the gap on each of the new plugs using a feeler gauge to be sure each one is correct. The proper gap for the 2001 Subaru Forester is 0.031-inch. Disconnect the battery cables, starting with the negative terminal, by loosening the terminal nuts with a wrench. Remove the battery from the Subaru.