How do you change a oxygen sensor in a 99 chevy tahoe?

I have a 99 chevy Tahoe and the sensors are bad I need to change them asap My daughter is coming home tomarrow and I am going to need the truck to pick her up 2 1/2 hours from home please help...|||They just unplug and unscrew, there may be up to four sensors though so make sure to change the right one(s). There is a small tab you push in to unlock the electric connector and they should slide apart. You may need an 02 sensor socket ava at autozone as a lonatool if you cant get a 7/8%26quot; wrench on them.|||Well you said you had 2.5 hrs 3 hours ago but you should also check the connecters you are plugging the new sensors into... %26#039;99 and %26#039;98 had a problem with the connecters and water, look for green stuff and the like. use a little dielct. greese in the new ones.|||depends on what sensor you wanna replace and also just a note only one sensor may go bad and not more than that. If you have say sensor 1 bank 1 and sensor 1 bank 2 going lean then I would check for a fuel pump going bad or a vacuum leak some where because they both never go out at the same time. Same thing if both banks for sensor 2 codes you really need to check the circuit first to see that there is no problems with it. It just may be an intermittant problem. Clear the light and drive around and see if light comes back on with same codes again. If it does have it diagnose and do not assume that just because you have an O2 code that its a bad O2 sensor. If you have a code for all 4 sensors that never happens so you really need to have diagnose for possible faulty ECM. You replace all 4 sensor and 100% sure the light will return for same thing.