Recently had the SES light come back on.

Decided to head the AZ and got a new PCV valve, and fuel filter to maybe help resolve the issue without having to do another major purchase to fix. Went and removed the MAP sensor and noticed some oil on the bottom of the sensor. Removed the mount/spring to get to the PCV valve and the entire valve was covered in oil, top and bottom. Not 100% sure if its supposed to be like this. Removed the O-ring and seemed to be ok but with a little build up on one side. Is this normal? If not this may be the reason why the MAP sensor's gone out, with oil getting to it??? Thanks in advance...this is starting to test my patience