Hesitation and intermittent lost power OB-2000

[Suby00]

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

[Andyjo]

From the start there it sounded like bad CV's... for some reason. my girlfriend has a 96 legacy, and it has that problem sometimes, i'll have to check it out, thanks!

[muse]

It's interesting that the code was for leaky exhaust and that the O2 sensor ended up being the problem. What did they want to do instead of replacing the O2 sensor? Is there an exhaust leak at all?

[Setright]

muse, the ECU thinks there is an exhuast leak because the O2 sensor is returning bogus values.

[muse]

Thanks for the answer. Ah, the wonderful world of computers!

[Suby00]

It's interesting that the code was for leaky exhaust and that the O2 sensor ended up being the problem. What did they want to do instead of replacing the O2 sensor? Is there an exhaust leak at all?

 

 

Apologies for the late reply.

 

As Setright said, the computer was reading bad signal from the front O2 sensor. There was some small leak after the sensor on the exhaust and the garage suspected that to be the problem for the CEL being on. That obviously could not have been the reason for the hesitation, so I insisted on changing the sensor and then the CEL disappear also. The car has been running fine since.

 

Greg