I put pacesetter long tube headers on my truck and put ths sensors pre and post in position on the right, I'm getting 02 high voltage code on the scanner. Do I need to place two more on the left and splice then to the harness to get a lower reading?

 

So you kept your cat and tapped a hole for the downstream O2? Your 2003 only needs one of each, no need to do left side. What exact codes are you getting?

 

The headers are tapped for the upstream and new cats are tapped as well I assume is for the down stream. You think I may have the pre 02 in the wrong place? Should the upstream go in the cat? I don't remember the number of the code just 02 voltage high