SES light on, then off

[Atom_West]

I got a Service Engine Light a few days ago. Went to Autozone and had a code P0135: o2 sensor.

I decided to wait until weekend to replace it. In the mean time, the SES light went off by itself.

Is the 02 sensor still bad?

2000 Z71 silverado, 5.3L, 4x4 241,000 miles

[95Sierra2500]

Yeah, your O2 sensor is acting up. Might as well replace it before it adversely affects fuel mileage.

[Nice rig]

Before you go off and buy a new sensor, check the connection. I had my light come on a while back and pulled an 02 sensor code, they wanted 70 bucks for new one. I went home and crawled under her and found the connection loose...reconnected and had the code cleared, never came back.