Check engine light on/off

Hi ,

I just replace both O2 sensors (front and back) and fuel pomp in my Sentra 96(automatic). When I reset the computer the check engine light is off. Car seems driving ok maybe is little weaker on low shifts (the check engine light is off). Unfortunately when I turn off engine and start it again the check engine light will go on again after few seconds. When I reset computer the light will be again off until I do not turn off and on engine. I talk to mechanic that replaces the parts and they told me that “my car is little slow on fuel circulation and I should drive a little in order to car readjust”.
I do not want drive with check engine light on. Could somebody give me any hints what
is wrong?

Amad

Follow his advice...also, bring the car to a dealer to have it checked using an OBDII scanner