So, I'm ordering a wideband. Instructions say at least 18" past the exhaust ports and before the cat.

Well, there's only about 1-2" between my flex pipe and my cat, and thus my Cat is nearer to the ports than 18".

Soooo, is it better to have the bung welded in before the cat and too close to the exhaust ports or to have it after the cat and far enough away from the ports?

Thanks-

 

After the cat can give false readings. I'd much rather go closer to the ports then after the cat.

 

I was told the Flex pipe and cat were 1 piece. That is why im getting it all for free..

 

Well they are both part of the downpipe, which is probably what you are getting replaced..

 

Since your second o2 sensor is pre-cat replace that one with the wideband then delete code p0420 with hp tuners if you have it. That's assuming your pre-cat o2 sensor is between 9 and 3 (ie mounted on the top side of the pipe). DONT PUT IT POST CAT (it defeats the purpose).

 

All second O2 sensors are post cat on Cobalts.....

 

Truth