What air intake system is on the car? Is it the stock square box and ribbed rubber hose going into the throttle body? Open it up and make sure there is an air filter in there, and replace it.
Or, do you have an aftermarket air intake setup, which would consist of a cone air filter and either a plastic or metal pipe running to the throttle body; if you have one of these, the car is expecting a change in its PCM programming (ie, a custom tune) to compensate for the changes in airflow.

Typically, the cause of both O2 sensor sides like that is due to some other issue, such (as mentioned) a vacuum leak (from one of the 4 hoses connected to the intake manifold), but more often, a dirty maf sensor is the cause. Remove the maf sensor, get some maf cleaner, and spray the maf sensor per directions on the cleaner.

Taking it to a dealer will do nothing but cost you a ****load of money, and they wont fix it by replacing the 2 sensors.