last night we cleaned out my KKM after my buddy had talked to a ford engineer that hangs out on his (older gen cougar) forums... The engie said that open filters are fine, and indeed better than the stock airboxes, however oiled filters such as the K&N are far worse for you in the long run. The problem comes into play with your MAF. Your sensor is actually a thin wire with another thin wire wrapped around it. Oil from these filters builds up on the wire and corrupts the signal. We tore mine apart last night after we cleaned my filter (and tb, man was that gross) all you have to do is unscrew the sensor from the top of the tube (unscrew the part the wiring harness plugs into) then pull it out carefully, one touch on that thin wire, and you've just bought yourself a new MAF. Mine was crudded up with oil, sure enough. To clean the sensor all you have to do is use some windoex or other non aerisol glass cleaner (dont use anything harsh like stp or simple green) spray that on the wire and let it set for about 5 minutes, then blow off the excess, and let it set until dry. Reinstall, reset your computer (pull fuses, unplug the battery, whichever way you prefer) and fire that bad boy up. After about 10 minutes of driving the computer recalibrated itself and it made a noticeable difference, i did not re-oil my kkm after we cleaned it, the guys at the shop tell me it wont get destroyed witout being oiled, and i dont want to be pulling apart that MAF often with the sensitive wires being exposed.... hope this helps...
