I think I'm having the exact same issue on my 03 WRX wagon that I just bought, but I am not sure. I don't want to go throwing money at it in hopes that it'll fix it, but I want it to be fixed. I need to hook up my wideband and see what kind of AFR's I'm running. Any other signs of a bad coil? I'm going to do a smoke test on it today and check for leaks.