DT Headers on 2003 SE o2 sensors are lean

[vinmonty]

Hi all,
I had my mechanic put my headers on for me. I bought the CEL and everything. Well he put the CEL on the first set of o2 sensors, not the rear set. He said he did this because he thought that this was suppose to be there since the driver side o2 sensor will hit the wall if it is not angled away. Now the truck is lagging while accelerating and drinking gas like crazy. I told him to put the CEL on the back o2 sensors and he said he'll do whatever I want but there's no way that the drive side o2 sensor will fit. I am lost guys, please help.

[Mirage]

They go on the rear ones, the rear ones only job is to make sure the cats are working, with the headers ditching the primary cats you have to fool them with the CEL's. If you put them in the front ones that actually do work you will mess up your fuel trims. With 90* CEL's they fit fine in the rear.

[vinmonty]

I understand that. But the the front driver side o2 sensor won't fit standing straight up, it's hitting a wall. Should I have him cut that wall? How does it not hit anyone else's wll?