2001 Nissan Sentra ENGINE LIGHT

I REPLACE MY COMPUTER IN MY CAR TWO WEEKS AGO, REASON THE COMPUTER HAS NOT BEEN WORKING FOR TWO YEARS. ONCE I REPLACE COMPUTER, I RECIEVED CODES FOR MAF SENSOR AND OXGYEN SENSOR FOR BANK 1. I REPLACE MAF SENSOR AND TWO UPPER OXGYEN SENSOR.

NOW COMPUTER SHOWS MIXTURE IS TO RICH.
CAR RUNS ROUGH WHEN STOP, IF YOU PUT CAR IN NUETRAL IT CLEARS UP. WHEN YOU TAKE OFF CAR MOVES SLOW, THEN IT CLEARS UP AND CAR GET POWER BACK.

WANDERING IF PROBLEM COULD BE DOWNWARD OXGYEN SENSORS, OR EGR VALVE. IS THERE A TEST TO DO.

ALSO DO YOU KNOW HOW MANY MILES DOES IT TAKE TO RESET COMPUTER.