Check the PCV hose running down the firewall. The hose is nutorious for leaking/cracking as it's made of plastic.
Mine had a small leak couldn't see until we touched it and it shattered. I was getting the same codes.
A lean code could also be the DPFE sensor not working if an EGR code is present.
1996 2.5LT V6 Contour ATX
My Tour+help/info pics
E0 rims, Gutted Pre-Cats,CTA Custom Exhaust & Intake, Diablo Chip.