Use OEM NGK plugs and Subaru wires (or at least high quality wires).
Have the wires ever been replaced?
Any check engine light?
Not all Subaru engines are so sensitive, and you don't say which vehicle/engine you have, but if you're posting here that suggests a newer EJ engine, all of which do better on the OEM NGK plugs.
Have the wires ever been replaced?
Any check engine light?
Not all Subaru engines are so sensitive, and you don't say which vehicle/engine you have, but if you're posting here that suggests a newer EJ engine, all of which do better on the OEM NGK plugs.
