No, you are not missing a hose. That is a vent that normally has a small piece of foam over it to prevent crappage entry. When you pull the hose off you have to plug it, or the vacuum leak will cause the engine to stumble and/or stall.
Thanks guys for pointing me in the right direction ....I found that it already was misfiring and when i took the hose off and sealed the air off as instructed i still was noticing a misfire...so when i revved the engine and watched my lever it would open at first and second rev then wouldn't move again which also caused me to think it was a vacuum leak so i had a buddy of mine smoke test it and found three leaks....both egr pipes (probably needs sealed or gasket repair whr the two screws are) and my injector number 6....thanks again. I got it getting repaired now should run like a champ now!!!!!!!