I'd stay away from oiled air filters. I dropped a K&N into my '11 F150 and a week later I got a check engine light. I took it in to the dealer and they said my MAF sensor took a ****. They changed it out, (thank god for warranty) three weeks later, another check engine light with the same problem. I switched back to a fram paper filter and its been about two weeks and so far do good.
Caused by too much oil on the filter and the maf being right after the filter on the f150.