I cleaned and oiled my K&N filter, I noticed on the front of the rubber piece, that connects it to the motor, a hole was drilled, it's probably 1/2 in round. I bought the truck used, is there supposed to be something there, I covered it up with duct tape, until I found out if it was drilled for a reason. Do they make a plug to stick in there....it seems like the filter would be useless with the hole there.

 

Could be either the hose or the sensor that goes there. Do you have the sensor connected already? what about the hose/tube?

 

I went and got a rubber plug and stuck it in the hole, hope I didn't hurt anything by driving it like that.