I doubt if Rousch sold whatever that thing is. Most intakes, whether Rousch, Edelbrock, Weiand etc are sold with no accessories included. It sorta sounds like a check valve in the vacuum line to the power brake booster in the front trunk. If so and it appears defective, throw it away as there's already one built into the booster itself.
PANTERA INTERNATIONAL
A DE TOMASO CAR CLUB
Presents the De Tomaso Forums
The On-Line Meeting Place for De Tomaso Owners and Enthusiasts From Around the World
Clicking on the banner will take you to the sponsor's website.