Before you replace any parts, check for vacuum leaks, check fuel pressure and even compression. A vacuum leak can cause both the O2 sensor the mass air flow and even the knock sensor by causing a misfire. Uneven cylander compression can cause any one of these codes also. Usually when there's more than one code at once, it's something completely different. I've seen dirty throttle plates cause a air mass meter code. Fuel pump relay's often cause a whole host of codes all at once.