Install went fairly smooth except two issues. First the MAF holes didn't line up perfectly with the venturi plate. Quick call to Air Force let me know it was ok to drill out the hole a bit to make it fit. Second issue was I got this left over part. It's a 3" black pastic piece with two different size tubes off the side. I'm assuming this piece is used for a 5.4 install, but the directions made no mention of it.

Anyhow, went for a ride diwn the highway and then back via side roads. No annoying noises or CELs. There is a definite difference in the breathing and feels real good between 3500 and low 4000's. Also gone is an annoying point in the throttle when cruising at @ 1900 roms and then hitting an uphill grade, the motor doesn't seem to kick down as badly as before. So far me happy.

 

Yeah, not sure what that part would be either.. I didn't have anything like that in my AF1 kit for '05 4.6L..

 

I believe this is a vaccuum hose connector if I am understanding you correctly. Older AF1 tubes has this molded in stainless but the 3.5" tube has the black plastic piece, at least mine did.

 

Here's the extra piece. Anita called me back this morning and she didn't know what it was and was going to follow up with AirForce.