I know it's been covered some time before, but a nice little reminder for those that haven't seen it- clean your MAF sensor- it's easy and cheap
The MAF is simply unplugged and then two phillips head screws (use a rather fine phillip head so you don't round the screws) and it's it out.
I use CRC MAF cleaner- $5 a can and specifically made to clean MAF's
Before and after pics of the MAF- first one it's black and kind of sooty looking, the second you can see the wires cleaned and the almost amber color of the "bulb". Simply give it several sprays from several different angles- let it dry good and put it back in.
This is a good time to throw a new filter in as well