KingSnake.
I wouldnt believe it if someone told me it, I would think they were just Bull Sh!ttn but when people put K&Ns on there new stangs they get a rough idle and real bad cold engine bogs.
The only thing I can think of, is that the K&N ACTUALLY flows that much better than the stock filter, that the computer doesnt know what to do. Several people have come up to me and TimC and the hangout and asked us wthat the problem is, we tell them to disconnect the battery for 5 minutes, or pull fuse 21, then after 5 minues connect them and drive the car like you stole it for about 15-20 minutes. No half throttle, either full wide open, or deaccerlerating.
Guess What....No more bog.
Same thing when a cold-air or throttle body is put on.