I noticed this tube on top of the intake and wonder if there is suppose to be something hooked to it? I bought the truck wrecked and thought maybe the original owner took a vacuum line off or something. He had the truck part way disassembled when I got it. It runs great. I did have an issue with it jumping out of drive to neutral, but found on here how to adjust the shift linkage and think I have that fixed. I think the wreck had moved the cab enough to put a bind on the linkage. Here is some pics of the tube. It's the smaller one toward the firewall. This is on a 2004 3.4 4x4 auto.