I want to start with thanking everyone contributing to the Message Board. A lot of invaluable info.
My problem started with the famous engine hesitation at low rpm when taking off at traffic lite for example. With time it was on and off and it got worse. The car started loosing power intermittently and I really had to press the gas pedal to get it going at times. When cold though (the first 5 min was just fine). Until a week ago when the CEL (Check Engine Light) came on. So I read all I could find about the "hesitating engine" on this Message board. Went to the Subie dealer and change the fuel filter first to no effect, then I bought the O2 sensor, but couldn't remove it from the exhaust. In the mean time I disconnected the connector (really tricky) and connected it again. The problem was a lot less obvious. I did drive the car for another day and went to the local garage to replace the sensor. They put the car on to computer and got the code for leaky exhaust system. I insisted on changing the O2 sensor. This was it, faulty O2 Sensor. Now the car is running like brand new again.
Thanks again to all contributors to this Message board.
Greg