I have a 2001 AVH engine code. The old O2 sensor seized and it came out with no threads. I have tried chasing the thread with a thread chaser, but the hole is hard to get to and I still do not know if I am going in square. Even if I got a thread tap, I am not sure that I could get it started square. I am thinking that I should remove the manifold to get the problem solved right. Has anyone tackled this problem before? Does the manifold come off without too much trouble? Can anyone give me knowledgeable advice? I simply cannot believe the way this car has been engineered for service. It is worse than any American car that I have ever worked on.