Suspecting I may have a vacuum leak I discovered a place where vacuum exist but no line is attached. Just beneath the hood latch is an electrical connection with a vacuum connection (see photo one). I placed my finger over the hole and there is suction.




Beneath that is a metal tube with what would could be a location for a vacuum line or something to attach.


The line T’s off to both sides of the car and end beneath the exhaust mounts (photos 3&4). The end of these tubes are also open.


Can anyone look at their car or a service manual and tell me if the line should be connected somewhere? Is it just a missing vacuum cap? Should the line be connected to the one below and then connected to something else.
As you could imagine your assistance is greatly appreciated in advance.

You need to plug the open vacuum line. Someone has replaced the stock muffler (with the vacuum operated bypass valves) and they forgot to finish the job. The device in the center of the first picture is the solenoid valve that controls the exhaust bypass valves. Normally a vacuum line runs down the back of the car from that valve, connects to a "T", then splits right and left and runs to the bypass valves located near each of the exhaust tips. The solenoid valve is "normally open", so unplugging the electrical connection will still leave you with a leak. Take a small length of rubber hose, connect one end to the solenoid valve outlet and plug the other end with a small bolt (or something similar).

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Thank's for the reply, I capped the vacuum line at the switch(Advanced Auto / Dorman part #47389 1/8), after speaking with John over at Laborghinitalk.com (great repair tips). According to him I don't have stock exhuast and as you stated someone didn't complete the job.I Couldn't take it for a test drive (Mother's day).

My wife just purchased the car for me and I'm wondering what performance issues it has suffered with the vacuum line open?

I have noticed an issue with, what I believe is the mixing door (making the drivers vents colder than the passenger's as well as hesitation and a sucking sound when shifting from 2nd to 3rd(getting on it of course). It would be great if this $.40 rubber cap could resolve those issues.

Some wife you've got there. It's Mother's Day and SHE buys you a Gallardo!

The small vacuum leak should not have any permanent consequences. It basically let additional (unfiltered!) air into the intake plenum, as if the throttle was slightly more open, but without this air going through the air flow sensor in the fuel injection system. This gave you a slightly leaner mixture and probably was not noticeable except at idle.

As for your other issue, I don't have a clue. Ventilation management systems are typically vacuum operated, so it could be an open/broken vacuum line. But vacuum goes away under full throttle, so I wouldn't expect to hear anything under those conditions. Either put up with it or have a trained technician look at the car.