Read this about testing your MAF:
http://sites.google.com/site/mikefocke2/checkenginelightcausedbymassairflowsensor
and this about changing your O2 sensors:
http://sites.google.com/site/mikefocke2/oxygensensors
If you go for replacement O2 sensors think seriously about getting ones with the factory type connectors that are simple plug-and-play. With a little research you can get them for around $100 apiece, which is what I paid. You'll read more than a few posts here from people who got univeral sensors for as little as $30 apiece, but there are a lot of potential problems. Using these isn't as simple as soldering on the factory connectors. Trying to save $ by going this route is penny wise, pound foolish IMO, but it's your car and your money.
Let us know how this turns out.