code 8=bad sensor
A new lc1 may have been overkill.
The gas analyzer in the tail pipe might show leaner than the lc1 because of the cats.

It would be interesting to see the lc1 vs. the gas analyzer with the gas analyzer it the opposite side of the lc1 instead of the tailpipe.
What was the Lambda reading from the lc1?
Did you calibrate before this test?