Are you guys changing the air filter with every oil change, once a year, or at different intervals? What filters are you using?

On my van, truck, and motorcycle, I use those filters that you can wash out and reuse.

 

The biggest fear is adding too much oil. I only add oil to the side facing the incoming air. I never add oil to the side facing the sensor. Then wait for it to slowly saturate. It's okay to go back, and add a little more if needed. If you add too much oil, then you have to clean it and start all over.

 

I can attest to the over oiling of the K&N filters thus I've discontinued using them after this set off a mass air flow sensor warning. I've since switched to the WIX filters as these are shallower by design. Also if one compares air filters.. One would see that the WIX filter is thinner by design than filters like Napa brand or CarQuest etc The Wix requires no oiling but achieve a performance aspect which is similar to the K&N filter without the oiling.