1999 Ford Taurus Misfire 303 and lean code 174 with code 40

I have a duratech with the 303 misfire code along with the 401 and 174 code I have replaced the egr valve the egr back pressure sensor the pcv valve the 2 down stream o2 sensors the coil pack wires plugs fuel filter the iac valve cleaned the maf sensor replaced the plentum gasket along with some other things I can't think of right now still has a rough idle and a misfire along with the codes