Grand Am problems

My '96 Grand Am SE has been giving me problems. My engine light came on, I had it checked out (from a friend who has his own diagnostic machine and he works for GM). He said I needed a new O2 sensor and he put one in. After I got my car back, I drove it a few minutes and then the light went on again. Now I have problems with the timing of speed change. I'll step on the gas and there is about a 10 second delay in reaction. The car also occasionally stalls on me, but I am able to restart it. Usually this stalling is when I am at a slow speed (at a light or turning). WHAT IS THE DEAL?!?:mad:

Something is causing your O2 to go bad. By scanning the vehicle the tech should be able to look at the readings and determine the problem. He should pull the codes out of the vehicle again and I bet you he'll come up with a different code this time. I had one the other day, a 2.4l and the throtle position sensor was out of wack. Replaced it and the car was fine. But get it scanned again first. Good Luck.

Depending on the engine you have, it could be computer problem or a major vacuum leak.

I agree with PCV on his advice to get it checked out again. But your O2 sensor is showing the problem it doesn't mean it is the problem. Often things are masked by the computer and a good rode test and some diag checks will pinpoint the problem. Sometimes as in this case the O2 sensor was a bandaid it might slow down the problem but not cure it.