[Dpc2u]

You disconnected them to remove the cover. The small one under the front, and the big stubby one in the drivers side back corner. If either of these were not fully seated and tight, that would have caused your issue. The only way to really know is to remove the plenum, which you did, reassemble it, and make sure everything is properly seated and sealing. That's really the only way to eliminate that possibility from the equation.