Where do dyno shops that do pulls with a wideband O2 sensor hook up the 02 sensor on a Maxima?

 

In the tail pipe.

 

Usually in the tailpipe, some will put it in an O2 bung if one is easily reached.

 

they got a little clamp they will clam on to the end of tail pipe

 

but aren't the exhaust gases coming out of the tailpipe filtered for fuel and combustion byproducts by the catalytic convertor(s)? And doesn't that have the effect of making a tailpipe wideband inaccurate?

 

Yes, that's one of the reasons why a tailpipe sniffer wideband is inaccurate. Have them put it one of the bungs on your ypipe.

 

so, in other words, have them remove one of my oem o2 sensors (or remove it myself) then have them insert the wideband probe?

How about removing the one at the exhaust header (it's at the front of the engine bay, right?)

My guess is that the pre-cats in the cali-spec Max y-pipe would throw things off, too...