problems with cold air kit

All right guys/gals I have another question. I put a cold air kit on my '03 F150 w/the 4.6. I had a check engine code come up (bank 2 running rich) and it might be the mass air flow, O2 sensor, vacum leak, or a spark plug. Wondering if this could be related to the cold air kit or something else. I have noticed discolored exhaust smoke when I start it up after sitting for a week or so. Lookin to see whay you can tell me...

over oiled filters will fuck up MAF's.

If they are over oiled, do you have to replace the sensor or clean it?