02 sensor codes will not stay off

[Scooter11]

Hi,

My 2003 Altima 2.5 SL has 117,000 miles. My service engine soon light came on. My code reader said it was both oxygen sensors & camshaft position sensor. The exhaust manifold also had a crack in it and was getting loud. So, I replaced the manifold (pre-cat) along with both 02 sensors, camshaft position sensor, spark plugs(recommended @ 100k). I have even replaced the rear catalytic converter.

Here is my problem. I erase the codes, drive the car for 30 miles, code stays off. When I restart the car, the SES light reappears and tells me both 02 sensors are bad. I could probably drive for 200 miles and they wouldn't come on again until I restart the car.

So, I took the 02 sensors I got from autozone back and bought bot sensors from nissan. I'm still having the same problem. At this point, I can't think of anything else that needs to be replaced, all parts on the car at this point come from nissan. Your thoughts?