I also put a K&N CAI and noticed the same type of "loss of response" but I think Stroker is right about the powerband changing. It seems like the truck is in too high of a gear at low rpms until it downshifts and the truck FLIES!!! I however did not notice any difference in the mpg which i was dearly hoping for! =)

I plan on a magnaflow/flowmaster upgrade soon so ill repost with results. I may try new platinum plugs and see if that helps with the response as well. we'll see.?.?