i need help. I recently hooked up my Vibrant Exhaust. Running great and i love the system, i noticed two plugs for the 02 sensor, i used the one before the cat because it was the only one i could reach with the plug and sealed the other one. exhaust ran great for 4 days and is still running great. but now 4 days later i have a CEL. could this be because of me using the one before the cat or would this happen anyways. or shouldnt it happen. it concerns me because i dont know if the CEL is from the exhaust since it went 4 days without having the CEL???