there is two 02 sensors on the manifolds, and one just before the 2nd big cat correct?. i have the motor pulled and the smog pump is removed and at the back of the motor theres a deal that has a yellow tube and a pipe going back to the 2nd cat what is that? was it hooked up to thesmog pump? do i need it? both cats are gonna be gone..

 

and what should i do witht eh 02 sensor that was by the 2nd cat?

 

when I did my exhaust, I cut everythin from the o2 sensor back. I also ditched the air injecteion (the yellow pipe you were talking about I think) when I put in my high flow cat.

 

okay well it looks like this http://i.ebayimg.com/00/s/NzY1WDEwMjQ=/$T2eC16dHJF8E9nnC8Hy1BQLVD+pU4g~~60_35.JPG
its the 3rd thing from the right almost looks like the thermactor

 

yes, that is the pipe from the smog pump to pump air into the cats, if your removing your cats just cut the pipe up towards the engine as far as you can

 

So can I just remove the whole thing

 

yes : if you dont have an 02 sensor after the cat and there isn't emissions testing in your area

 

It would help if you identified what engine you have along with the model year. I'm going to guess it's a '96 since you've got three O2 sensors. If you remove either the cat and/or any the O2 sensors you will set a OBD2 error code. That would likely result in an inspection failure if you have them. Keep in mind, you might not have them today, but you could tomorrow.

At this point, most states are "writing off" pre-'96 vehicles since they make up such a small percentage of the "population". But given how easy it is to "test" '96+ vehicles via the OBD2 port, they will be subject to testing for some time to come.