You need to remove the O2 sensors before the cat and using a special tool, check for back pressure. If they are bad, the only thing you can do is replace them.
September, 1, 2011 AT 2:05 AM
The special tool goes in the hole where the oxygen sensors were then? I don't need to actually remove the cat to inspect it?
September, 1, 2011 AT 2:08 AM
Yes, the pressure gauge screws into where the O2 sensor is removed. As far as the cat, you will know if it is bad by the back pressure. NOTE: When they plug, often times they will get so hot, they glow red hot.
September, 1, 2011 AT 2:30 AM
Thanks for the info, I appreciate it.
September, 1, 2011 AT 2:49 AM
Glad to help. Let me know if you run into other questions.