ok so i replaced my donut gasket on the stock headers cause of its common leak. now the check engine light is on and throwing a p1166 which is a 02s. i took it to autozone to turn off the light and its came back on right away. i dont understand before i started to fix it no check egine and now there is one. HELP!!!!

 

help help

 

check your sensors. maybe one is f'd up or something

 

Did you accidentally yank on one of the wires...Take them out clean them, and re-install...make sure the wires aren't in contact with any metal. When my heatshiel took a dive it yanked the wire and it caused me to throw the o2 sensor code...