stalling on 2003 Cadillac CTS

I recently had an o2 sensor replaced, now when I go in reverse the vehicle stalls and when I am driving there is a slight shaking and the engine feels like it is going to stall when stopping. It does not occur every time I drive. Could you give me any suggestions?

Asked by of J & P Automotive Incorporated for the 2003 Cadillac CTS
vaccuum leaks are the most common reasons for stalling.
is the check engine light on??
what was your issue prior to replacing the o2 sensor.

1 more answer , 1 more comment
This is going to require an inspection to determine what is going on. If you just had a shop replace the O2 sensor then I suggest taking it back to them.
How long has it been since you had this repair done? Did this occur right after the repair?
I bet he took it to a parts house and they told him he needed to change his O2 sensors and he did, by himself, and that didn't fix the problem. Now he has to spend some real money to address the problem. Just guessing.