So the 97 XK8 I've bought recently passed smog about 5 months ago but I had to smog it again for change of ownership. It did not pass for me today. I used guaranteed to pass on it per instructions but like I said, it failed. It has a new cat was tuned up as part of the deal. So I guess what I'm asking is what am I looking at here a sensor a new engine or something inbetween. Any advice is appreciated.

 

I suppose we need to know why it failed.
Did you get a report or had the codes checked?