Guys,

Car - 93 SC400.

I have searched and found 1 thread about code 27 - sub O2 sensors but I didn't fully understand the exact problem so if anyone can elaborate I would appreciate it.

I recently had a dual exhaust put on the car - would this be why it is doing this?

Is the code for either the cat or the 02 sensor? Is there just 1 sensor? any help would be appreciated as to what the possible problem may be related to. Thank you,

Jonny