Hello everyone..after alot of work putting spark plug non foulers in the back 02 sensors, I go and get the light turned off and in 8 miles its back on! Iwas told this would work by a friend and reading about it but it didn't and the reading from advance still says the P0153 02 sensor slow response bank 2 sensor 1..so i'm wondering what is going on it appears to be a bad sensor..but why right after i had the X pipe put on..the MIL Eliminators didn't work either I had no light before i messed with it..Its very flusterating to work on this and come up with no good results, it was pretty hard to put those Spark plug non foulers on the 02 sesors and 2 drill bits later and numourous cuts LOL..but what i'm seeing its the Front passenger side sensor by Advance auto parts testing machine and the guy that works there has a mustang and knows alot about stangs..If any has a suggestion I'm open thanks so much..