catalytic converter

So, I am replacing my exhaust with a flowmaster exhaust. I was going to just do the Cat back system, but I got underneath the vehicle and realized that it is a dual catalytic outlet to a single muffler inlet. I know that flowmaster has a direct fit catalytic converter for my vehicle. The...

I have a 96 Tahoe, and I am experiencing horrible fuel mileage!!! I have a check engine light - showing a bad catalytic converter. But, does this give me under 5 mpg? Also - do I have to replace them or can I just cut them out! Any or ALL help will be appreciated!:Insane:

Does anybody know anything about a replacement plug for the post-cat O2 sensor plug? Some guy re-programmed my ECU/PCM and did a O2 delete (from what I'm told) and has since disappeared. But the last thing he said was not to start the truck until a filler plug is in place. From what I'm...