I have a 98 Tahoe that I purchased a few months back. total problems so far are losing o/d and today it started knocking bad. its not out of oil and the knock seems to be coming from the bottom of the motor. the codes said bank 2 system too lean,manufacturer controlled fuel and air metering, manufacturer controlled transmission. as well as a misfire.sby my name you should know I have no idea where to start. but the term knock sensor and bearings were talked about when I had a buddy take a look earlier. any ideas or input is greatly appreciated. o yea and sometimes at around 70 MPH it starts to stutter