Outback wagon with multiple codes...

This is an Outback wagon, 2.5 l, 2001. The P0171 comes on almost immediately after it gets cleared. The P0130 takes a few cycles to show back up. I know what the codes mean, I'm wondering if the two are related and what the most obvious fix might be. Also, at idle the rpm seems low and tends to search up and down. Other than that, there are no drivability symptoms or problems.

Any ideas? Thank!

I don't have a code list in front of me but IIRC one of those is the MAF sensor.