I tried to take > the bung off of the elbow but that thing is on there > like flies on ***You have to use a large socket (27mm I think) with an impact wrench. The rear O2 sensor (B14) is smaller and is 12mm x 1.25 (thanks Ray). ===== Jay Whitely Tampa, FL 1996 200SX SE-R GTi-R powered, F-MAX Stage 2