Hey guys and gals. I've got a P0171 code from my 2006 2.0l ZX4. It will occassionaly run rough and loop when idling. Once I give it some gas, it runs fine. I've tried looking for a vacuum leak visually and with the carb cleaner trick with no luck. After searching the net, I came across an post about the IAC valve and thought it might be it. I took it off and cleaned it (even though it wasn't really dirty), but it didn't fix it. I played with it some more and noticed that while it was running rough, I could unplug the IAC and the car started running fine. Plug it back in and a second or 2 later it acted up again. I replaced it but still have the problem. Where should I look next?