I have a 2002 Rendezvous and love the car. In the last month our Check Engine light has turned on three times. Each time, it indicated a failed O2 Senser on Bank 1. There are two. The computer keeps pointing to the one behind the catalytic converter (#2). After replacing it, I can drive about 30 miles before the check engine light comes back on. Any idea what is going on here? Can the Catalytic converter somehow be causing this?