i used maf cleaner made by CNC and yes i just got the K&N filter about a month ago and oiled at that time.. the MAF looked like new but i cleaned it anway since then..
from my understanding even though the misfire goes away when i unplug the MAF, thats just showing that the MAF IS working and that the problem is somewhere else.. i would think its an air/fuel issue and not ignition because unplugging the MAF wouldnt effect an ignition issue and the misfire would still be there.. i think..
i get what sounds like a vacuum leak sometimes when at idle in gear once the car is warm but can not find it.. i have tried spraying every where with carb cleaner and did the smoke test but nothing.. maybe the sound of fluid running through a line somewhere sounds like a whistle? seems to be coming from under the truck near bell housing/engine area..
heres a video of the whistle.. around 30 sec is when you can hear it..