You need a can of throttle body cleaner and a soft toothbrush. Spray and brush the TB on both sides of the blade. You also need to inspect and CAREFULLY spray the Mass Air Flow Sensor(it is delicate). The problems with K&N, Amsoil and other aftermarket filters usually occur in high dust areas, like when wheeling in a group kicking up lots of dust,(you could stick a fresh factory or Fram paper filter in just for the short time off road). The other cause of aftermarket filter problems is over oiling when they are cleaned. My buddies shop has never had a customer with a problem using a new K&N on the road. But off road, because they do allow more flow(less restriction accomplished by allowing larger particles to pass through), you can clog the MAF pretty quickly. Mojave