Rough running truck!

Ok, I'm just hoping someone has a idea of what to check for this... It's a '01 F150 w/ a V6.

My truck ran great for about 20 minutes, then i stopped to talk to my dad for a few minutes and left it running, right as I got back in, it made a little noise that I can't really describe and started idling very rough. The only "symptom" that I'm noting is that the sucking noise at the air filter is a LOT louder now.

It really seems like a vacuum problem to me, but I don't see anything disconnected... any suggestions?

I just had it all apart to move the wiring harnesses on the firewall into the truck, but I didn't un-do anything other than those harnesses... The only thing still not mounted properly is the cruise control unit, but I can't imagine that's an issue for this...

Anybody have a diagram of all the vacuum lines so i can be sure i'm checking them all?

there is one that goes into the intake tube from the valve cover, check that one.

c any slpit or dry-cracked vacuum lines??

those trucks are also notoriious for intake gaskets to. there is one line goin from the valve cover to the back bottom of hte uppper intake manifold that is a crappy plastic one.

I came across the answer on accident... mass air sensor was bad... unplugged it and it ran great so I put a new one on and it's all better, I never would have guessed that it was that critical of a sensor!

yea all the sensors are critical on an OBDII pcm