I recently had my check engine light come on about a month ago for a code p0133 and p0153 so i replaced both number one o2 sensor on each bank. This seemend to fix the problem, but just yesturday i got the same 2 codes again. And i have checked the wiring and its all in good condition. and my air/fuel gauge is constintly on lean, and every now and again its stays on rich . can anyone please give me another opinion on why this problem keeps coming up.