I have three codes - low sec air flow and bank 1 and bank 2 cats low efficiency.

I've looked at vacuum lines and don't see any leaks. Don't see any leaks in the sec air flow suction or discharge lines to the fan. The fan runs. I have not pulled the Kombi valves.

Also, I checked the vacuum from the vacuum valve to the Kombi valves- none- although there is vacuum to the valve. Does this valve only open at cold engine temps?

Or could these codes all be caused by pre-cat O2 sensors?

Thanks