93 ciera code 44

i have a 93 cutlass ceira. just installed a new 02 sensor disconnected battery to reset codes and it came back on. when i take off sometimes it hesitates real bad and when im cruising any speed the check engine light will come on for a short time and go off when the chech engine light is on the engine runs rough untill the light goes off. just installed new fuel pump. had checked by mechanic said everthing was ok could it be the pcm , or the maf sensor ? i dont know to check them, or can they be checked?:banghead:

This points to a lean mixture, not a bad sensor. Misfire, low fuel pressure, vacuum leaks, all possibilities that require proper diagnosis.