I got 4-1 headers an custom exhaust done up.

Headers->Cat->Glasspack->Muffler

I looked an the shop put my second O2 sensor before the cat.
So I know its only a matter of time before I start throwing CELs or even burnin out the sensor.
By what means can i prevent this?
I know extending the wires of the O2 sensor, then putting it after the cat, how its suppose to be, but this would cause me to get a whole new mid section pipe re-done since there would be a hole in the pipe where it used to be...

 

Get a short bolt with the same size threads as the 02 sensor and put it in the unused hole.

 

you can actually get a plug for an O2 sensor bung. I have one from when I had my exhaust done...i had to extend the sensors myself so I had them weld on the bungs and plug them 'till I could get to it. They might have them at your local auto shop...or just go to a muffler shop and ask for one.

 

where's your first O2 sensor???

 

My first one is in the header.
The second one is the one im worried about. Cause if that goes, the ECU is going to start duming fuel an its going to kill performance an gas milage. frown

 

The second o2 sensor is there only to make sure the cat is working. Its for EMISSIONS ONLY.

If you throw a CEL, make the shop move it behind the cat.