Have you fitted anything else other than the wideband, and of course the obligatory question: Do you have the OEM air intake, or a pod filter?
What other mods do you have? (how about a non OE blow off valve?)

I notice your logs are at 1300 RPM, which is high for idle unless you are still warming up or your engine is struggling with a vacuum leak.
Is the air volume raw MAF Hz?