scanned car yesterday and today

[milleniumz]

I threw a code for O2 sensor, passenger side, before cat and it said low voltage. I went ahead and bought the only two they had and replaced the drivers and passenger before the cats. Erased code and 50 miles later, same code. I just bought the other two O2 sensors and will be changing today.

Anyone have this problem before. I have 89K on the car so replacing them is not a big deal. Just would like to know about the "low voltage."

Thanks

[2001NBMZ28]

P0151? Could be the connector or one of the wires hitting the exhaust, along with a couple other possibilities - www.gearchatter.com/viewtopic9048.php