what do i need to do to make my 323ci(2000)run properly on 2000 BMW 323Ci

when i bought car i started replacing all sensors o2 all 4 of them the maf sensor the rear exhaust manifold due to broken weld on cat i have replaced all vacuum lines i can think of including air intake. will start upt and run fine. then it will in about 5 minutes engine light comes on and starts with codes 1188 and 1189 o2 sensors then it throws fuel bank trim codes misfire on all 6 cylinders.. please help at wits end

Asked by for the 2000 BMW 323Ci