Maybe im just dumb, but DirtyHarry brought up a good moint. Maybe someone that knows more about these particular things can elaborate upon what he said </font><blockquote><font size="1" face="Verdana, Tahoma, Arial, Helv, Helvetica, Sans">quote:</font><hr /><font size="2" face="Verdana, Tahoma, Arial, Helv, Helvetica, Sans"> I think that the most telling sign is that it does not happen when the the motor is cold and in open loop mode. That tells me that the problem is a sensor and not a mechanical item like the cat or valve seals. If it were the cat, you would have the problem all of the time, not just after it warms up. </font><hr /></blockquote><font size="2" face="Verdana, Tahoma, Arial, Helv, Helvetica, Sans">