Your car uses a 3-solenoid electronic EGR valve. These solenoids are what you are referring to as the EGR "sensors". Replacement of the EGR valve is the fix. It is mounted on the upper plenum near the throttle body. It takes less than 5 minutes to change (it's mounted by two 10 mm bolts and has one wire harness plug in the center), but that is one expensive valve. An AC-Delco runs $210.69, and Advance and Auto Zone sell theirs for about the same.