Mil light on code suggested weak mixture, checked for air leaks, non found, scoped both oxygen sensors and AMM waveforms attached.

Question is 1. Why so much noise on AMM pattern, leads kept away from all sources of interference.
2. The pre cat sensor appears to be switching
ok post cat sensor has high reading suggesting rich mixture and cat not doing very much.
3. Long and short term fuel trims hovering around 100 +/- 15% how much bearing will the post cat sensor have on the long term trim.

When code is cleared and adaptions reset the Mil light stays out for exactly 85 miles

!T





Any thoughts appreciated