Okay, I just got back from my local import mechanic shop (old friend of mine). He has a new young apprentice, so he was eager to look at the values my scanner recorded.

Based upon what I was told, the long term value should be at 0% and no higher than 3%. The 16% on bank 1 and 17% on bank 2 is way out of specs. Also the -11% and -13% I am seeing on the short term is indicative of the ECM trying to lean out a very rich condition.

He believes there is excess air getting into the system (vacuum line, etc), which is causing this condition. The cat theory he was not sold on. He said that the O2 sensor after the cat would pick that up and pop a code.

He is recommending a "smoke" test to look for the leaks.

I'm still open to suggestions from the forum ... please, don't be shy!