Rough idle, stalls when stopping or turning, drinks gas and exhaust smell. Codes are PO131 PO135 & PO171. I've changed the oxygen sensor. In the process of changing IAC valve.

What is your question?

Please help

What makes this problem better or worse?

Having the AC on seems to make it worse.

How long has your 2001 Buick Century had this problem?

Since having the vehicle but doesn't do it every time I drive.