I got a front o2 sensor CEL a couple weeks ago and was told by sub to have a new one installed. Instead I bought a slightly used one (10k or so) and had my mechanic friend install it for me. The CEL came back. After testing the sensor, my friend says that it is stuck in a constantly lean state, and that this is usually not due to a bad o2 sensor. Did i buy a bunk sensor? is there a bigger reason for the sensor to be stuck lean?
My car has really poor performance and starts to choke around 3-4k, ie no power. Also, if I keep the pedal down while its choking aruon 3-4k the CEL will flash.
Any suggestions before I give up and have subaru look at it? I do have a competent mechanic, but he does have a scanner for live data, and says he can't properly diagnose further,