To see that the exhause hanger that supports the pipe just after the Cat has rusted around were its bolts to and is free haning so i removed it, and resorted to 2 metal coat hangers, i fixed them up in there quite well until i can get a new hanger and put it in. Also how do i know if i need a new CAT for sure, im getting poor mileage and it idels bad but is there any physical way i can tell for sure?

The poor milage and rough idle are more likely the front O2 sensor. The Cat is for clean air, you could remove it and fake the rear O2 sensor but you wouldnt pass the air care test if needed too?

Its a new O2 sensor....whats the chances that its a bad one ....NGK... Also i scanned it for codes and its not throwing anything

93'* don't have the O2 after the Cat, a bad cat can be identified by shaking or kicking it. If you hear a rattle, chances are it'* time for a new one.

An O2 sensor rarely throws a code when they go bad. They just get weak. Does your exhaust smell rich?

yeah it smells rich, makes the garage smell bad if i fire it up and dont back it out right away...

I'd suggest getting an AC Delco O2 sensor. Regardless of the age of the NGK. I used a Bosch for 60 days (bought it new) and had to replace it. I'm not a fan of anything Bosch on our cars, and usually like the NGK, but this is now the second fairly new NGK O2 sensor I've seen here that may be suspect.

Part numbers for the O2'* are in Techinfo, just run it through www.gmpartsdirect.com

Much better than dealer price. There is some risk of shotgunning here, but the O2 is the primary cause of running rich 90% of the time.

Best way to tell for sure if your cat is backed up is by taking temp readings before and after the cat. Either buy a decent digtal thermo that has a high range or take it to a shop and ask if they could check for you. The temp right before the cat should be very close if not exactly the temp after the cat. If the temp before it is higher then your cat is backed up. As I understand this is industry standard for checking the cat.