Possible Causes:

WARNING: This page does not describe the selected car, but rather 7 other vehicles, including the 2007 Ford RV Cutaway, 2007 Ford Pickup, 2007 Ford F550 Super Duty, 2007 Ford F450 Super Duty, and 2007 Ford Econoline. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: Reset the air filter restriction gauge after repairing a restriction concern.

Snow or foreign material restricting the airflow at the air inlet
Misrouted air cleaner ducting
On engines recently repaired, rags or cap plugs may have been inadvertently left in an air inlet pipe
Tailpipe or muffler may have collapsed or been damaged