Anyone That Can Help,

I have a 95 M3 that is my pride and joy!! My car just turned 160,000 miles. About a year ago I started to have a problem with the Oxygen Sensor. I threw a check engine light and ran my code reader to find that it was an Oxygen Sensor issue. I took the car to my mechanic who replaced the Sensor and all was well (or so I thought). I have replaced the Sensor 3 times in the past year after repeated check engine lights and new sensors. I trust my mechanic who specifically works on BMW's completely but he cannot figure out what the issue is. He has run wires bypassing all relays to make sure that itís not a relay or wiring issue. He has installed and run the car with a different OBC, which failed to fix the issue! I figured I would turn to you guys for any advice or to see if anyone has experienced the same issues. I would appreciate any input that might be of assistance! Thanks Guys!