The facts are these:

-I bought an '88 N/A the other day and it's having trouble idling and starting.
-The engine was recently rebuilt and the previous owner said it ran fine at first.
-He said that after installing Turbo II brakes it would die if the engine speed dropped below 3K RPMs.
-When I picked it up I noticed that after I got it started (roll off) it idled fine with the clutch depressed.
-I looked at the vacuum connections associated with the master cylinder and the hard line downstream of the passenger side canister is capped off: Master cylinder - hard line - pass. side canister - hard line - cap on drivers' side.
-I also noticed that the 3.5mm vacuum line connection on the drivers' side of the dynamic chamber was not connected to the 'Switching Solenoid Valve' as per the FSM. I could not locate this valve.

I do apologize if this is a common question, but I could not find anything with the search. Even if you don't know what's going on, pictures of the drivers side of a stock N/A FC3S would be very helpful and greatly appreciated. Thank you for your time.

 

It definitely sounds like you have a large vacuum leak on your hands. The factory service manual (FSM), which is free to download (http://www.rotaryheads.com/PDF/2nd_gen/index.html), may give you the help you need in looking for a leak. The switching solenoid should have a gray plug, blue is relief, orange is the FPR & yellow will be the EGR solenoid. Look for uncapped hard lines on the emissions rack, or anything else that stands out. I'd also take a look at the brake booster vacuum lines, since the problem seems to have occurred after brake work was done.

 

vacuum leak would be my guess also.