the code is for low voltage on the after cat O2 sensor...

On other cars this typically means it's a busted sensor...

search around for a reasonably priced direct replacement. I had one go on another car of mine... OEM sensor was $130 but I found a direct replacement Bosch sensor for $25 new... looked identical to the one I took off the car too.

If the after cat sensor died it could be signs of a failing cat...

What I would do: first clean the plug... unplug it spray both sides of the connector with contact cleaner (found at radio shack or other electronic stores) and plug and unplug the sensor a few times, if that doesn't work, replace the sensor.

there's no harm in cleaning your MAF (or cleaning anything for that matter)... typically if the maf is dirty you'll have a rough idle too...

I suppose if the maf was dirty it would throw off the map and cause the engine to run out of spec resulting in low sensor readings...