Threw a P0507 code...

[Geof3]

So looks like I have some troubleshooting to do. Started the car up today and it was a little cranky. Unusual. Seemed to run fine, after about 30 min at a stop light noticed the idle climbing a bit. Shut it down at Starbuck's, we did our thing, and started right up and seemed fine. Stopped to get some food, climbing idle and threw the CEL. Checked at home, P0507 is the only code that came up. Cleared the code, idle is normal, but a bit rough, accelerating just fine. I cleaned the throttle body a bit ago, no noticeable smoke, and haven't noticed any other issues. The only engine component I have changed recently is the water pump and low temp thermostat. Also added an oil pressure sensor. Bled system as described in the Bentley manual, temps/levels seem fine. Thinking MAF, poss AOS, maybe vacuum leak somewhere? Thoughts?