Okay well i just redid my entire exhaust from header back changing it to true dual. after the install i started the truck and it didn't want to idle to well so i checked the scan tool and it was running rich for some reason in bank to so i checked the o2 voltage in that bank and the voltage was staying the same so i assumed the sensor went out so i replaced it and that didn't fix it. so my next guess was the wire got burnt or shorted somewhere from the harness so i ohmed out each wire in the plug to each pin in the harness and they all checked out good and weren't broken anywhere. So this is where im stuck i don t know what to do from here because i have no clue what could of went wrong. also i did weld on the header but the edu,battery everything was disconnected so i don't see anything getting fried if it was all unplugged. another thing i thought it was is i couldn't fully weld the v band flange all the way around due to the floorboard of the truck so i though it was evacuating air through there making the sensor run lean causing it to run rich in that bank. But other than that im lost if anyone can help i would appreciate it.