The CPS is a pain because it's tight down there. The issue is a little lip which holds the clip to the sensor. You have to carefully pry that little plastic clip up so when you pull on the connector to unplug it, it will indeed be able to be pulled off of the CPS.
As far as vacumn lines, I'd just say check everywhere. If you've had / or done any service recently it could be it wiggled off or was never reattached. There's one that goes down to the TB area that may have been pulled off or cracked. Also, if you've been messing with the CPS, there's one that connects to the top of the engine that could have been pulled off.
Good luck.
It has been stated that unscrewing the bolt holding the CPS in place and then releasing the latch is the best way to do this job.