4 Wheel Drive/SUVs: Toyota 4Runner O2 Sensor, toyota 4runner, o2 sensor

Question
Hello,

I have a 2000 Toyota 4 Runner (V6) with 80K miles. Recently, the "check engine" light came on. The mechanic did a diagnostic check on it, and the error code was 147 (O2 sensor). The light would come on for a day or two, then stay off for a day or two. My gas mileage plummeted. They replaced the sensor, but that didn't work. After two days at a dealership, they finally said a wire at the sensor was loose, and that their was two gaskets used instead of one. This doesn't sound right to me. What do you think?

Thanks.

Answer
If the problem is fixed it sounds to me like another mechanic caught someone elses mess up. The previous mechanic probably damaged the wire and either didn't know it, or didn't act as he did. So in my opinion it was a shotty mechanic that did your work to begin with. The O2 sensor will cause the gas mileage to drop and cause drivability problems as well. Did they get the light to stay off? if it is fixed now, as I said I believe the mechanic the first time knew he could have you back in again if you know what I am saying.

Matt