Wonky O2 Sensor Codes?

[Bmwtvboy]

First, it's been a great ride and enjoyable journey. Now at 260K miles this 01/3.0 auto is showing age.
1. When using the cruise control the SES pops on, then the EML and cancels out the c.c. Code states Lean n Rich bank 1 & 2. But there is also ICV stuck open code. Drives ok after this.
2. Clear codes, SES pops on, but codes only read Rich/Lean 1 & 2 banks.
3. Sometimes SES stays on for a day or so and cancels itself out. But then days later pops back on with the same reading.
Not seeing any great decline in MPG as I record against mileage every fill up.
Acceleration seems normal, but definitely not spirited and snappy on the pedal.
4. Only time ICV stuck open codes is when I use the C.C.
O2's were all changed out around165-170 miles from original ones.
What should my plan of attack be? I don't want to throw money at it.
I know I have to clean up the ICV asap. I have to check/test CCV as well.
But what about those pesky O2 sensors?
Thanks.