If anyone can help me. I've got a check engine light on an '03 WRX that reads a misfire in cylinder 1. I've had the coil pack replaced and the plugs and plug wires are good. I figure that the most likely issue is the fuel injector. The light only comes on after longer drives and stays on most of the time, but occassionally dissapears mysteriously along with the miss it brings. I don't really notice a performance difference, but you can definitely hear the miss when the vehicle is parked and idling. I think I'm hearing a knock at low rpms as well. I was going to run some injector cleaner through it and replace the fuel filter, but I'm not sure where the fuel filter is. Has anyone out there replaced injectors themselves? How big of a job is it? Thanks ahead of time.