I got the trouble code 44 oxygen sensor lean. I have replaced the O2 sensor but I still keep getting this code and the engine turns off & has lost power. What could cause this?[&:]

 

Exhaust leaks ahead of the O2 sensor can cause a lean reading on the O2 which will inturn cause an overly rich condition in the engine as the PCM tries to compensate. Also, inadequate fuel pressure can cause a lean condition.

By the OBD1 code, I can tell you are working on a 1st generation blazer, but please post your vehicle information including the motor type (TBI or CPI) for more specific diagnosis.