Unhook one of the O2 sensors downstream of the cat. You should eventually get a cat efficiency code, but it won't hurt your car.
This sensor does nothing for setting fuel mixture or timing. Like I said, it
measures cat converter efficiency.
It may take a while, as mentioned above, drivecycles and all, so run out and do it now, drive it around for a while, then research it
You could probably leave your gas cap loose and get a
code from that as well. Don't think that does much harm.
Unless of course you go to the dealer and have them check
it for ~$100 to tell you to tighten the gas cap.
TB
