Originally Posted by F.I. Inc.

Fern,

If it is exhaust related it is due to one of two things.

1. You have an exhaust leak in front of that rear O2 sensor. What that means is it could only be one place. The connection point between the resonated test pipe and the stock exhaust manifold at the 3 bolt flange.

2. One or both of the O2 sensors was either mis handled and has oils on the probe, or they get damaged during the installation.

That is it, it cannot be anything else. Call me directly if you have any questions...

Thanks, Tony