Sounds like you're looking in all the right places already. Did you also verify that the air cleaner assembly was closed up like it should be? Those codes point to vacuum leaks though,m as you already know, they don't pinpoint a thing. I have looked at vacuum lines before and thought they were good only to replace them and discover they were bad but just not where I could see it.
Vacuum hoses, when compared to )2 sensors are too cheap not to try and replace them before you spend the time and money on O2 sensors. Just my two cents worth.
Vacuum hoses, when compared to )2 sensors are too cheap not to try and replace them before you spend the time and money on O2 sensors. Just my two cents worth.