Has anyone had a code problem with the T-6 yet. I am having a steady Po420 code. I took the word of a dealer and replaced the cat, to no solution. They had the car for 3 days and couldn't fix it. I ended up replacing the rear o2 sensor and it worked for awhile and then came back. Replacing the front o2 sensor looks nearly impossible, by the way the angle is. Has anyone have a clue on why this happens, and any idea on how to replace the front o2 sensor. There are no other codes showing. Thanks.