Sometimes the Check Engine Light illuminates because the computer detects misfires. Subaru released an improved spark plug wire set to solve the problem. The ignition coil should also be inspected for carbon tracks or short circuits between the contacts
Engine Misfire Due to Failed Spark Plug Wires on Subaru Impreza Outback Sport
Average mileage: 104,000 (104,000–104,000)
Engine affected: 2.5L 4 Cylinder
7 people reported this problem
2009 Subaru Impreza Outback Sport - 2.5L 4 Cylinder 104,000 mi, Visitor
Check engine light came on while driving and showed cylinder 4 misfire. Leaking spark plug gasket.