I've read that some shops weld a fitting in the exhaust to hook the wideband up to. Would this be to get a reading before cats? Because I'm wondering, since on my last dyno, the o2's don't match the wideband(sensor in exhaust tip) at all <img border="0" title="" alt="[Confused]" src="images/icons/confused.gif" /> . If the cats are messing it up, then hey, there's my reason to go ahead and get headers now <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" /> . Graphs and spreadsheets can be found in the "Got my tnt dry kit on the dyno today" thread to get an idea of what I mean.

On a side note, my a/f according to the wide band was completely opposite of what it's supposed to be, i.e. richest at torque peak and then lean out on the way up.